• Sportsdirect.com Retail Ltd v Guru Invest SA (Comm). Acting for Sportsdirect’s Icelandic franchise partner to defend a claim against Sportsdirect for breach of contract.
• ARC Capital Holdings Ltd v ARC Capital Partners (Comm) [2015] EWHCA 2170 (QB). Acting for defendant in a claim for negligent investment management by a Hong Kong-based hedge fund.
• Terra Firma v Citibank. Acted for Terra Firma in $2 billion claim arising out of the acquisition of EMI in 2007.
• UBS v Kommunale Wasserwerke Leipzig GmbH [2014] EWHC 3615 (Comm.); [2017] EWCA Civ 1567. Acting for the claimant, UBS, in a US$320 million misselling claim seeking to enforce payment under a number of synthetic CDO transactions
• Forsta AP v Bank of New York Mellon [2013] EWHC 3127 (Comm). Acting for BNYM to defend a claim by the Swedish national pension for losses incurred in the course of securities lending.
• Harbinger Capital Partners v Caldwell [2013] EWCA Civ 492. Acting for the independent valuer in a claim by former shareholders challenging the valuation of Northern Rock following its nationalisation in 2008.
• Berezovsky v Patarkatshvili (Chancery). Acting for the family of deceased oligarch Badri Patarkatsishvili in a multi-million claim by his former business partner Boris Berezovsky.
• Lehman Brothers International (Europe) v Lehman Brothers Bankhaus (Frankfurt Higher Regional Court), concerning the cross-border application of the FSA CASS rules on the treatment of client money.
• Re Sigma [2009] UKSC 2, now the leading case on the interpretation of commercial contracts, concerning the application of the security trust deed governing the distribution of assets of Sigma Finance Corporation following its collapse in 2008.
• Atrium European Real Estate Ltd v Meinl Bank & ors (Commercial Court), a multibillion euro fraud claim arising out of underwriting and market making activities carried out in Austria on behalf of a Jersey investment fund and raising complex issues of jurisdiction involving the Judgments Regulation, common law rules and arbitration provisions.
• Lacrosse v Royal Bank of Scotland (Chancery Division), concerning the interpretation of the termination provisions of the 1999 ISDA Master Agreement.
• Natixis v. (1) WestLB (2) CIBC (3) Terra Firma (Commercial Court). Acting for Terra Firma in its defence of a £100m claim for fraud and negligence in connection with the structuring and sale of securitised notes.
• Ernst & Young v Edmund Hor. Acting for EY in a claim for a success fee due following the negotiation of a business transaction.

• Advising the London branch of a major Gulf bank on compliance with MiFID 2.
• Advising a UK high street bank on the enforceability of its standard interest-rate variation clause.
• ARC Capital Holdings Ltd v ARC Capital Partners (Comm) [2015] EWHCA 2170 (QB). Acting for defendant in a claim for negligent investment management by a Hong Kong-based hedge fund.
• Terra Firma v Citibank. Acted for Terra Firma in $2 billion claim arising out of the acquisition of EMI in 2007.
• UBS v Kommunale Wasserwerke Leipzig GmbH [2014] EWHC 3615 (Comm.); [2017] EWCA Civ 1567. Acting for the claimant, UBS, in a US$320 million misselling claim seeking to enforce payment under a number of synthetic CDO transactions
• Forsta AP v Bank of New York Mellon [2013] EWHC 3127 (Comm). Acting for BNYM to defend a claim by the Swedish national pension for losses incurred in the course of securities lending.
• Harbinger Capital Partners v Caldwell [2013] EWCA Civ 492. Acting for the independent valuer in a claim by former shareholders challenging the valuation of Northern Rock following its nationalisation in 2008.
• Lehman Brothers International (Europe) v Lehman Brothers Bankhaus (Frankfurt Higher Regional Court), concerning the cross-border application of the FSA CASS rules.
• Re Sigma [2009] UKSC 2, now the leading case on the interpretation of commercial contracts, concerning the application of the security trust deed governing the distribution of assets of Sigma Finance Corporation following its collapse in 2008
• Atrium European Real Estate Ltd v Meinl Bank & ors (Commercial Court), a multibillion euro fraud claim arising out of underwriting and market making activities carried out in Austria on behalf of a Jersey investment fund and raising complex issues of jurisdiction involving the Judgments Regulation, common law rules and arbitration provisions.
• Lacrosse v Royal Bank of Scotland (Chancery Division), concerning the interpretation of the termination provisions of the 1999 ISDA Master Agreement.
• Natixis v. (1) WestLB (2) CIBC (3) Terra Firma (Commercial Court). Acting for Terra Firma in its defence of a £100m claim for fraud and negligence in connection with the structuring and sale of securitised notes.

• Eurasian Natural Resources Corporation Ltd v (1) David Neil Gerrard (2) Dechert LLP (Comm). Acting for Dechert LLP and Dechert partner Neil Gerrard in defence of a claim for professional negligence and malpractice by mining conglomerate ENRC.
• Barrett v Deloitte LLP (Chancery). Acting for Deloitte LLP in defence of a claim for negligent tax advice by the former manager of pop star Sade.
• Pegasus Management v Ernst & Young [2012] EWHC 738 (Ch). Acted for Ernst & Young in defence of claim for negligent tax advice, including issues of assignment of loss between successive claimants.
• Baxendale Walker v Middleton, Law Society & ors [2011] EWHC 998 (QB). Acting for PwC in defence of a claim against an expert witness who had given evidence against the claimant in disciplinary proceedings before the Law Society
• Akai Holdings Ltd v Ernst & Young (Hong Kong High Court). Acting for EY,to defend a US$1 billion audit negligence claim arising out of the collapse of the Akai Group.
• Orient Power Holdings v Ernst & Young (Hong Kong High Court). Acting for EY in defence of an audit negligence claim.
• New China Hong Kong v Ernst & Young (Hong Kong High Court). Acting for EY in defence of an audit negligence claim.

• ICC arbitration between two oil & gas exploration companies concerning the application of an "area of mutual interest" provision (London seat) 
• ICC arbitration between oil & gas exploration companies concerning a dispute under a joint operating agreement (Singapore seat) 
• ICC arbitration concerning a dispute under a gas supply agreement for a power station (Singapore seat) 
• SCC arbitration between a Russian oil company and the Republic of Ukraine in a claim under the Russia-Ukraine bilateral investment treaty (SCC, Stockholm seat) 

Jonathan has broad experience of acting in and advising on commercial arbitration in a wide range of arbitral fora including under ICC, LCIA, UNCITRAL, ICSID and SCC rules and in the Permanent Court of Arbitration, including:

• UNCITRAL arbitration between a London-based investment bank and a Kazakh state company concerning a claim under a guarantee (London seat)
• LCIA arbitration under a business separation agreement concerning the division of assets and obligations between former business partners (London seat)
• Advising on a possible claim against Interpol in the Permanent Court of Arbitration
• ICC arbitration between two oil & gas exploration companies concerning the application of an "area of mutual interest" provision (London seat) 
• ICC arbitration between oil & gas exploration companies concerning a dispute under a joint operating agreement (Singapore seat) 
• ICC arbitration concerning a dispute under a gas supply agreement for a power station (Singapore seat) 
• ICSID arbitration concerning a claim by a Cypriot bank against the Greek state under a bilateral investment treaty for losses incurred in the Greek debt crisis (Swiss seat).
• SCC arbitration between a Russian oil company and the Republic of Ukraine in a claim under the Russia-Ukraine bilateral investment treaty (SCC, Stockholm seat) 
• LCIA arbitration between an international tobacco company and its Iranian distributor (London seat)

Jonathan has experience of advising in a wide range of situations involving sanctions, embargoes and travel restrictions under UN, UK and EU provisions, in particular with regard to how they may affect commercial transactions.

• VTB v Council Case C-729/18P. Acting for VTB in an appeal to the CJEU challenging its listing under measures directed at Russian financial institutions in response to events in eastern Ukraine in 2014
• Yanukovych v Council Case C-598/16 P. Advising President Viktor Yanukovych of Ukraine in his challenge to EU sanctions imposed following the Euromaidan protests of 2013-2014.
• Advising a Hungarian individual on challenging INTERPOL’s publication of a Red Notice seeking his arrest and extradition.
• Advising an English company on sanctions implications in a contractual dispute with an Iranian state-owned company.
• Advising a bank on issues arising under export control legislation in connection with the financing of naval vessels for an African country.
• Advising a US company on the impact of global sanctions on a contract for oil export with the Libyan government. 

• Tenant, Brick Court Chambers 2006-2015 and 2017-
• Partner, Joseph Hage Aaronson LLP, 2016-2017
• 2005 Call (Lincoln's Inn)
• Pupillage at Brick Court Chambers, 2005-2006.
• Stagiaire in the cabinet of Judge Forwood, Court of First Instance, European Court of Justice, 2005.
• Macmillan publishers, 2001-2004.

• Languages: French (fluent), Polish (fluent), Italian (conversational).
• Semi-finalist, University Challenge (2003-2004 series).

• Cambridge University (Trinity College) (BA 1997; MA 2005; MMath 2011)
• Harvard University (MA 2000)
• London Metropolitan University (G. Dip. Law 2004)
• Inns of Court School of Law (Bar Vocation Course 2005)
• Scholarships & Prizes
• Junior & Senior Scholar, Trinity College Cambridge
• Frank Knox Memorial Fellow, Harvard
• Hardwicke Award, Haldane and Denning Scholarships, Lincoln's Inn
• CPE Award for best mark in year, London Metropolitan University
• Charles Grant Tennant Prize for Light Verse, Trinity College Cambridge