Professional practice
Luke practises as a barrister specialising in international arbitration and litigation. He has particular expertise in public international law, including investment treaty arbitrations, along with complex jurisdictional challenges and large-scale litigation.
He is presently acting in cases before the International Court of Justice, Inter-American Court of Human Rights and the European Court of Human Rights. He has acted in arbitral proceedings under the ICSID, UNCITRAL, ICC, PCA and LCIA rules, along with arbitration related court applications in the UK and overseas.
Luke regularly advises both State and non-State parties across the full range of international law issues. Recent work has included challenges to the enforcement of investor-State arbitral awards, jurisdictional applications based on State immunity, issues of State responsibility concerning attribution, various points of international humanitarian law in on-going armed conflicts and issues of international human rights law under the ECHR and UN Conventions. He also regularly advises on the law of economic sanctions, principally under the United Nations, European Union and UK sanctions regimes, this includes advising on individual designations as well as travel bans, asset freezing and arms embargoes.
Many of Luke’s cases involve the application of foreign law and he is used to working with expert witnesses and lawyers in other jurisdictions to prepare reports and submissions.
Alongside practice, Luke teaches Public International Law at Cambridge University and is on the editorial boards of the Journal of International Peacekeeping and the International Journal of Human Rights. He has published work concerning investor-State arbitration, State immunity, the conflict of laws and various aspects of international litigation. He was awarded the Lalive Merryman Fellowship at the University of Geneva for research published on the subject of State immunity.
- International Arbitration
Luke has extensive experience in both investment treaty and international commercial arbitration. He has worked on cases under the ICSID, UNCITRAL, ICC, PCA and LCIA rules along with ss.67, 68 and 69 appeals, as well as the enforcement of arbitral awards against both companies and States.
Examples of investment treaty arbitrations include:
- Middle Eastern Investors v African State (UNCITRAL): Acting for the respondent State in claims under bilateral and multilateral treaties concerning damage caused to infrastructure during an armed conflict.
- United States Investor v South Pacific State (ICC): Acted for the respondent State advising on various issues of international law in relation to an ongoing arbitration with a United States investor.
- European Investors v Asian State (UNCITRAL): Acted for the respondent State in proceedings relating to the enforcement of a USD$ 1.5 billion arbitral award obtained under a BIT. The challenge was based on various points of international investment law and the law of State immunity.
- European Investors v Asian State (UNCITRAL): Acted for investors in a substantial arbitration against an Asian State brought under multilateral and bilateral investment treaties concerning claims of harassment by the State’s security services and judicial corruption in the municipal courts.
- European Investors v European State (UNCITRAL): Acted for investors in an Achmea jurisdictional challenge brought by the European Commission concerning proceedings commenced under an intra-EU BIT.
- Advised in relation to the recognition and enforcement of a series of arbitral awards obtained under the UNCITRAL rules and administered by the Permeant Court of Arbitration in The Hague. The case raised issues regarding State immunity, the New York Convention, freezing injunctions against foreign States and security from the English courts whilst the awards were being challenged in jurisdictions abroad.
- Advised in relation to the recognition and enforcement of several arbitral awards obtained against CIS States. The case concerned detailed examination of the State Immunity Act 1978 and the likelihood of obtaining interim-remedies pending execution of the awards.
- Junior counsel to Paul Key KC acting on behalf of Nigeria in Process & Industrial Developments Ltd v The Federal Republic of Nigeria [2018] EWHC 3714 (Comm) concerning relief from sanctions regarding the enforcement of a USD$ 9 billion arbitral award.
- Advised on jurisdictional issues arising under a bilateral investment treaty and whether investments were excluded if made in breach of the host-State’s domestic laws.
- Advised in relation to claiming moral damages under public international law for non-pecuniary loss arising as a result of a State’s actions undertaken through its police and security services.
Luke has also published numerous articles and book chapters on investment treaty law, including in the European Yearbook of International Economic Law and The Law and Practice of International Courts and Tribunals.
Examples of international commercial arbitrations include:
- An ongoing LCIA arbitration for a United States company concerning the recovery of investments made in a multibillion dollar project in Northeast Africa.
- An ICC arbitration concerning breach of contracts for the international sale of goods. The case featured heavily around the application of the principle of force majeure.
- Drafted the statements of case for an LCIA arbitration concerning a complex share purchase agreement being undertaken in East Africa.
- An UNCITRAL arbitration concerning breach of a guarantor agreement for sums loaned to state-owned entities in Central Asia.
- Prepared a substantial Section 67 Arbitration Act 1996 appeal regarding whether or not the tribunal had jurisdiction to hear the case.
- Prepared a Section 68 Arbitration Act 1996 appeal to overturn an award on the grounds that the tribunal had failed to deal with all the issues put to it.
- Advised numerous companies and State-entities on the enforcement of commercial arbitration awards in the English courts.
Luke authors and edits the chapters on international arbitration in The Encyclopedia of International Commercial Litigation, (Kluwer Law International) Mr Justice Bryan (Ed).
- Public International Law
Luke has particular expertise in public international law. He regularly acts as counsel in cases before international courts and tribunals, including the International Court of Justice and the European Court of Human Rights. He acts as counsel in investment treaty arbitrations under bilateral, multilateral and regional investment agreements concerning a range of treaty standards, including expropriation, fair and equitable treatment, most favoured nation and national treatment provisions. He has advised on the recognition and enforcement of arbitral awards against States and has experience of the law of State, consular and diplomatic immunity, State responsibility and the extraterritorial application of States’ laws.
Luke has also advised on a range of United Nations and European Union sanctions regimes as well as issues of international humanitarian and human rights law. In 2020, he was awarded the Lalive Merryman Fellowship to undertake research in international law at the University of Geneva.
Examples of general international law matters include:
- Acting for Azerbaijan in two sets of proceedings before the ICJ: Armenia v Azerbaijan concerning actions arising out of the armed conflict in 2020; and Azerbaijan v Armenia concerning claims arising from Armenia’s occupation of Azerbaijani territory since the 1980s and the related hostilities. Following oral hearings, the ICJ handed down two provisional measures orders in December 2021.
- Acting for six Portuguese children who have brought claims against 33 States before the European Court of Human Rights (Duarte Agostinho & Ors v Portugal & 32 Other States App no. 39371/20) in relation to the States’ failures to take sufficient action to prevent climate change. The claims concern Articles 2, 3, 8 and 14, extraterritorial jurisdiction, exhaustion of domestic remedies, victim status, and State responsibility.
- Advising a group of children and young people from a range of European countries who have brought claims before the European Court of Human Rights against 12 States on the basis that their membership of the Energy Charter Treaty (ECT) breaches the applicants’ rights to Articles 2, 3, 8 and 14 of the Convention on the basis that the ECT is prohibiting action to stem the pace of climate change (Soubeste & Others v Austria & 11 Other States).
- Advising States on a range of issues concerning State responsibility and attribution under international conventions and customary international law in relation to matters of armed conflict, genocide, torture, discrimination and human rights.
- Advised on issues of Statelessness and asylum under the UN Conventions on Statelessness and the Hague Convention on the Conflict of Nationality in relation to non-recognised States.
- Advised on the drafting of bilateral and multilateral Free Trade Agreements and Memorandums of Understanding between States in the Africa and Asia-Pacific regions.
- Advised extensively on issues of State immunity in relation to jurisdiction before the English courts as well as issues of enforcement against commercial and public property held by States in the United Kingdom.
- Advised on issues of consular and diplomatic immunity under the Vienna Conventions on Diplomatic and Consular Relations with regards to employment disputes, including the enforcement of judgments and awards.
- Advised on issues of United Nations and European Union sanctions regimes in relation to arms embargoes, travel bans and asset freezing, including the process of obtaining exemptions from sanction measures.
- Advised on the United Nations Security Council’s powers under Chapter VII of the UN Charter with regards to threats to peace and acts of aggression.
- Advised on issues concerning the foreign act of State doctrine and its application to matters undertaken by foreign States within their territories.
Examples of international investment law include:
- Middle Eastern Investors v African State (UNCITRAL) Acting for the respondent State in claims under bilateral and multilateral treaties concerning damage caused to infrastructure during an armed conflict.
- United States Investor v South Pacific State (ICC) Acted for the respondent State advising on various issues of international law in relation to an ongoing arbitration with a United States investor.
- European Investors v Asian State (UNCITRAL) Acted for the respondent State in proceedings relating to the enforcement of a USD$ 1.5 billion arbitral award obtained under a BIT. The challenge was based on various points of international investment law and the law of State immunity.
- European Investors v Asian State (UNCITRAL) Acted for investors in a substantial arbitration against an Asian State brought under multilateral and bilateral investment treaties concerning claims of harassment by the State’s security services and judicial corruption in the municipal courts.
- European Investors v European State (UNCITRAL) Acted for investors in an Achmea jurisdictional challenge brought by the European Commission concerning proceedings commenced under an intra-EU BIT.
- Advised in relation to the recognition and enforcement of a series of arbitral awards obtained under the UNCITRAL rules and administered by the Permeant Court of Arbitration in The Hague. The case raised issues regarding State immunity, the New York Convention, freezing injunctions against foreign States and security from the English courts whilst the awards were being challenged in jurisdictions abroad.
- Advised in relation to the recognition and enforcement of several arbitral awards obtained against CIS States. The case concerned detailed examination of the State Immunity Act 1978 and the likelihood of obtaining interim-remedies pending execution of the awards.
- Junior counsel to Paul Key KC acting on behalf of Nigeria in Process & Industrial Developments Ltd v The Federal Republic of Nigeria [2018] EWHC 3714 (Comm)concerning relief from sanctions regarding the enforcement of a USD$ 9 billion arbitral award.
- Advised on jurisdictional issues arising under a bilateral investment treaty and whether investments were excluded if made in breach of the host-State’s domestic laws.
- Advised in relation to claiming moral damages under public international law for non-pecuniary loss arising as a result of a State’s actions undertaken through its police and security services.
Luke has also published numerous articles and book chapters on the law of investment treaties, including in the European Yearbook of International Economic Law and The Law and Practice of International Courts and Tribunals.
Examples of international humanitarian (law of armed conflict) and human rights include:
- Advised in relation to questions of international humanitarian law under the four Geneva Conventions of 1949, their additional protocols and the Rome Statute of the International Criminal Court, concerning the treatment of civilians during times of armed conflict.
- Advised on the interrogation techniques and pre-detention conditions of prisoners being held abroad in respect of their rights under customary international law as well as the obligations under the United Nations Convention Against Torture, the Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights.
- Advised on the legal distinction between national and international armed conflicts and the applicable rules of international humanitarian law under each.
- Advising applicants on the prospects of bringing a claim in the European Court of Human Rights for breaches of Article 2 (right to life) and Article 8 (right to respect for private and family life) of the ECHR.
- Advised in relation to a State’s international human rights obligations when enforcing the death penalty for individuals convicted of serious crimes and the prospective challenges which could be brought in the domestic courts.
- Advised on issues of State responsibility concerning the actions of paramilitary forces and other non-State actors in armed conflicts.
- Advised on the compatibility of United Nations and European Union sanctions with respect to the European Convention on Human Rights.
- Advised on issues of international law applying to the transfer and sale of weapons under various international conventions, including the Arms Trade Treaty, the Cluster Munitions Convention and the Anti-Personnel Landmine Convention.
Luke is also regularly engaged by the Legal Directorate of the Foreign, Commonwealth and Development Office of the United Kingdom to provide advice on a range of public international law issues.
In addition to practice, Luke has published numerous articles on international law covering State immunity, the enforcement jurisdiction of States abroad, the effectiveness of investment treaties within the European Union and abuse of process before the International Court of Justice. He is also well versed in the law of the World Trade Organization.
- Private International Law
Luke’s cases regularly raise difficult jurisdictional issues across the full spectrum of private international law, including challenges based on forum conveniens, the Recast Brussels and Rome Regulations. He has experience of seeking antisuit injunctions along with the recognition and enforcement of both judgments and arbitral awards.
Examples include:
- SKAT (the Danish Customs and Tax Authority) v Solo Capital Partners LLP & Ors [2021] EWHC 974 (Comm); [2022] EWCA Civ 234: Acting (with Alison Macdonald KC) for three defendants in High Court and Court of Appeal proceedings concerning a US$2 billion fraud claim brought by the Kingdom of Denmark in relation to a jurisdictional challenge based on the extraterritorial enforcement of sovereign authority abroad (i.e. the rule in Government of India v Taylor). The case also concerns detailed examination of matters arising under the Recast Brussels and Lugano Conventions.
- The Kuwait Public Institution for Social Security v. Al Rajaan & Ors: Acted for and advised a defendant on issues of jurisdiction and foreign law in respect of claims brought by Kuwait in relation to allegations of fraud exceeding US$ 847 million over a twenty year period.
- Assisted James Collins KC and David Davies KC in preparing the case of Willmont v Elm International Ltd & Ors in relation to service of a claim outside the jurisdiction on seven defendants domiciled abroad.
- Prepared an application for an emergency ex parte antisuit injunction to restrain foreign proceedings which had been brought in breach of a jurisdiction agreement.
- Advised on whether re-litigating matters in England which had been dealt with before the courts of Russia and Ukraine would constitute issue estoppel and abuse of process, the case raised points of res judicata.
- Advised on the recognition and enforcement of judgments in England that had been obtained by State-owned entities in Russia.
- Assisted David Davies in Paradiso v Vdovin. The case raised detailed points concerning service out under the Recast Brussels Regulation and the CPR.
- Advised on the recognition and enforcement of English contempt of court proceedings – including the possibility of extradition – against defendants domiciled outside of the European Union.
- Advised on obtaining a stay of proceedings where parallel litigation had been commenced in the United States as well as in England.
Luke regularly works on cases governed by foreign law and is used to liaising with expert witnesses in preparing submissions, examples of foreign law cases include: Russia, Switzerland, Kuwait, Denmark, Singapore, Thailand, Belize, China, Hong Kong, Kyrgyzstan, the Cayman Islands, the British Virgin Islands, the United States (federal law) and New York.
Luke authors and edits the relevant chapters on jurisdiction in The Encyclopedia of International Commercial Litigation, (Kluwer Law International) Mr Justice Bryan (Ed).
- Human rights & civil liberties
Luke’s human rights practice centres around cases involving public international law where issues of human rights and civil liberties are engaged, examples of recent work include:
- ECHR climate litigation: acting for six Portuguese children who have brought claims against 33 States before the European Court of Human Rights (Duarte Agostinho & Ors v Portugal & 32 Other States App no. 39371/20) in relation to the States’ failures to take sufficient action to prevent climate change. The claims concern Articles 2, 3, 8 and 14, extraterritorial jurisdiction, exhaustion of domestic remedies, victim status, and State responsibility.
- Advising a group of children and young people from a range of European countries who have brought claims before the European Court of Human Rights against 12 States on the basis that their membership of the Energy Charter Treaty (ECT) breaches the applicants’ rights to Articles 2, 3, 8 and 14 of the Convention on the basis that the ECT is prohibiting action to stem the pace of climate change (Soubeste & Others v Austria & 11 Other States).
- UN human rights law: acting for Azerbaijan in two sets of proceedings before the ICJ under the Convention on the Elimination of All Forms of Racial Discrimination: Armenia v Azerbaijan concerning actions arising out of the armed conflict in 2020; and Azerbaijan v Armenia concerning claims arising from Armenia’s occupation of Azerbaijani territory since the 1980s and the related hostilities. Following oral hearings, the ICJ handed down two provisional measures orders in December 2021.
- Civilians in armed conflict: advised in relation to questions of international humanitarian law under the four Geneva Conventions of 1949, their additional protocols and the Rome Statute of the International Criminal Court, concerning the treatment of civilians during times of armed conflict.
- Torture and cruel, inhumane & degrading treatment: advised on the interrogation techniques and pre-detention conditions of prisoners being held abroad in respect of their rights under customary international law (jus cogens) as well as under the obligations arising from the United Nations Convention Against Torture, the Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights.
- UN Human Rights Council: advised government departments extensively on the process and amendments to the language of UNHRC resolutions, primarily in relation to human rights in armed conflict zones in Africa and the Middle East.
- European Convention on Human Rights: advising applicants on the prospects of bringing a claim in the European Court of Human Rights for breaches of Article 2 (right to life) and Article 8 (right to respect for private and family life) of the ECHR.
- Death penalty: advised as to a State’s international and human rights obligations under the International Covenant on Civil and Political Rights when enforcing the death penalty for individuals convicted of serious crimes and the prospective challenges which could be brought in the domestic courts.
- International sanctions: advised on the human rights implications of enforcing United Nations and European Union sanctions regimes against individuals in respect of Russia and Libya.
- UK sanctions: advised extensively on listing under the UK’s Global Human Rights Sanctions Regulations in relation to sanctions imposed on the basis of allegations of torture and slavery.
Whilst studying, Luke was awarded the Advanced Public Law Prize for coming first in the year on a course analysing the European Convention on Human Rights.
- International Environmental Law
Luke has a significant practice in international environmental law, particularly where it arises within the context of public international law.
He regularly advises States, NGOs and individuals on issues of international environmental law in the context of claims arising out of the European Convention on Human Rights, as well as a series of UN and EU environmental treaties and constitutional provisions.
Examples of environmental cases include:
Acting for a group of Portuguese children and young people who have brought claims against 33 States before the European Court of Human Rights (Duarte Agostinho & Ors v Portugal & 32 Other States App no. 39371/20) in relation to the States’ failures to take sufficient action to prevent climate change. The claims concern Articles 2, 3, 8 and 14, extraterritorial jurisdiction, exhaustion of domestic remedies, victim status, and State responsibility.
Advising a group of children and young people from a range of European countries who have brought claims before the European Court of Human Rights against 12 States on the basis that their membership of the Energy Charter Treaty (ECT) breaches the applicants’ rights to Articles 2, 3, 8 and 14 of the Convention on the basis that the ECT is prohibiting action to stem the pace of climate change (Soubeste & Others v Austria & 11 Other States).
Advising litigants in environmental litigation before the Guyanese Constitutional Court, concerning public law challenges to oil and gas exploration based on the constitutional right to a healthy environment.
Acting for farmers in judicial review proceedings brought against the UK government concerning regulations on the control of livestock.
Acting for a number of farmers in judicial review proceedings brought against the UK government concerning forceful construction over arable land and protection of the relevant ecosystems.
- Asylum and Refugee Law
Luke regularly acts in asylum and refugee proceedings in both the immigration tribunals and appellate courts.
Examples of recent work include:
Advising NGOs on the interpretation and application of the Refugee Convention concerning changes being made to asylum laws across States in the European Union to limit the rights and access to services of asylum seekers.
Acting for a range of applicants held in immigration detention centres pending determination of their asylum and visa immigration applications. Appearing before First-Tier Tribunals as well as the Upper Immigration and Asylum Chamber.
Acting in judicial review proceedings concerning challenges to the UK government’s policy to deport asylum seekers to Rwanda (the UK-Rwanda Migration and Economic Development Partnership), on the basis that decisions taken by the Secretary of State for the Home Department were in breach of the Human Rights Act 1998, the Refugee Convention and the European Convention on Human Rights.
- International Fraud & Asset Recovery
Luke has a range of experience in financial crime concerning States, individuals, companies and banks. He has assisted with obtaining a range of remedies in relation to the location and seizure of assets including freezing injunctions, proprietary injunctions, charging orders, search orders, asset preservation orders, Norwich Pharmacal relief, Bankers Trust relief and third-party debt orders. Examples include:
- National Bank Trust v Yurov & Ors [2020] EWHC 100 (Comm) Acted (with Nathan Pillow KC, David Davies KC and Anton Dudnikov) in a nine-week trial and consequentials concerning a US$ 1 billion fraud claim brought by a private Russian bank against its former directors and their wives. The case was governed by Russian law.
- Suppipat v Nop Narongdeg & Ors Acting (with Anna Dilnot KC and Helen Morton) for three defendants in a US$2 billion fraud claim brought by the former owner of Thailand’s largest renewable energy company. The Claimant fled Thailand prior to allegations of extortion and kidnapping. As a result, he sold his interest in the energy business to a Thai family and now seeks to reclaim it on the basis of an alleged conspiracy.
- SKAT (the Danish Customs and Tax Authority) v Solo Capital Partners LLP & Ors Acting (with Alison Macdonald KC) for three defendants in proceedings concerning a US$2 billion fraud claim brought by Denmark for the reimbursement of withholding tax.
- The Kuwait Public Institution for Social Security v. Al Rajaan & Ors Acted for and advised a defendant in claims brought by the public body of Kuwait responsible for social security and pensions in relation to allegations of fraud exceeding US$ 847 million over a twenty year period.
- DMC Building Machines v Her Majesty’s Revenue and Customs [2020] Acted (with David Scorey KC) for the appellant in a two-week trial concerning allegations of an orchestrated scheme to defraud the UK Treasury through European commodities trading.
- Ex parte application, United States company v international bank Acted (with Richard Edwards KC) in an ex parte application for Norwich Pharmacal relief seeking information to commence claims concerning purportedly fraudulent activities.
- LCIA arbitration concerning a significant monetary claim arising from a metals fraud perpetrated by way of a series of repo transactions.
- Advised in relation to the fraudulent transfer of shares. The case raised issues concerning the tort of deceit, tort of intimidation, breach of fiduciary duties, conspiracy and dishonest assistance.
- Assisted Paul McGrath KC and David Davies KC in Willmont v Elm International Ltd & Ors [2017]. The case concerned whether a number of high value properties which are being held in offshore trusts, subsidiary companies and Liechtenstein foundations are beneficially owned by an individual who had filed bankruptcy, to satisfy a judgment debt of US$ 195.5 million.
- Advised in relation to an alleged gold fraud. The case raised issues of the tort of conversion, along with proprietary and domestic freezing injunctions.
- Advised in relation to directors’ liabilities under the corporate veil regarding claims for conspiracy and deceit in fraud.
- International Cultural Heritage
Luke regularly advises States and NGOs on issues of international cultural heritage, arising under a broad range of international agreements and domestic regulations.
Recent cases have included:
Two claims before the International Court of Justice acting on behalf of Azerbaijan against Armenia concerning claims of destruction to cultural heritage caused during times of armed conflict and occupation.
Advising a State on matters arising under the Convention Concerning the Protection of the World Cultural and Natural Heritage and how to obtain UNESCO certification and site visits.
Advising an NGO on possible claims arising out of the The Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict regarding damage caused by non-State actors to national monuments in conflict zones in the Middle East.
Advising an NGO on possible claims for damage to art and cultural heritage artefacts caused during times of occupation under the right to protection of property (Article 1 Protocol 1) of the European Convention on Human Rights.
In addition to practice, Luke lectures on these issues, examples include a conference held by the Institute of Art and Law at Queen Mary University, London discussing sovereign immunity in art and cultural heritage disputes. His research in this area has been published in the International Journal of Cultural Property, for which his article concerning the restitution of expropriated art was awarded the Lalive Merryman Fellowship by the University of Geneva.
- Career
2019–: Teaching at the University of Cambridge
2018: Tenancy at Essex Court Chambers
2017: Pupillage at Essex Court Chambers
2016: Called to the Bar (Gray’s Inn)
- Education
2016/17: LLM, Wolfson College, University of Cambridge (First Class)
2012/15: LLB (Hons), St Chad’s College, Durham University (First Class)
- Awards
2020: Lalive Merryman Fellowship, University of Geneva
2017: Jennings Prize, Wolfson College, University of Cambridge
2016: Sir David Williams Scholarship, Wolfson College, University of Cambridge
2016: Wright Rogers Law Scholarship, University of Cambridge
2015: Prince of Wales Scholarship, Gray’s Inn
2015: Dean’s Award, Bar Professional Training Course
2015: Prize for Advanced Public Law, Durham University
2013/15: University Commendation x3, Durham University
- Publications
Luke regularly writes on topics of interest, recent publications include:
Books:
Co-author and editor of The Encyclopedia of International Commercial Litigation, (Kluwer Law International) Mr Justice Bryan (Ed).
Contributing author, Supperstone, Goudie and Walker: Judicial Review (6th edition) Helen Fenwick (Ed).
Journals:
The Law Quarterly Review – international humanitarian law
The Law and Practice of International Courts and Tribunals – abuse of process before the International Court of Justice
The European Yearbook of International Economic Law – investor-state arbitration
The African Journal of International and Comparative Law – jurisdiction
The International Journal of Cultural Property – state immunity
Lloyd’s Maritime and Commercial Law Quarterly – the extraterritorial application of states’ laws
The Journal of International and Comparative Law – no oral modification clauses (New York and English law)
The Law Quarterly Review – estoppel by acquiescence
The European Journal of Law Reform – chancery litigation
Trusts & Trustees – chancery litigation
Trust Law International – proprietary estoppel