Barney specialises in banking, investment banking, derivatives, fund management, financial markets and financial infrastructure, payments, fintech, crypto and digital assets, insurance and reinsurance law and regulation, and enforcement actions. He has particular expertise in UK and EU regulation, but also advises on navigating legal and regulatory systems worldwide. He has special familiarity with Abu Dhabi Global Market (ADGM), having set it up, and Dubai International Financial Centre (DIFC).

Barney is a leading thinker on how law and regulation affects commercial activities. He provides strategic advice to financial services firms on how to plot the most efficient course through law and regulation in a domestic and cross-border context; on the use of legal reasoning to achieve legal and regulatory certainty; and in engaging productively with the regulators and government officials. He assists firms in planning for and managing emerging risks from legal and regulatory change. He advises C-suites and Boards on business issues through a legal and regulatory lens. He has helped numerous well-known clients with business transformation.

Barney advised the UK government and numerous businesses in the context of the legal and other implications of leaving the EU, and how to navigate them. He has conceived and established new legal systems in the Middle East and elsewhere. He is interviewed and published widely, regularly writing articles in national newspapers. He speaks at conferences on global developments and participates in fora of regulators with new ideas for the application and adjustment of regulation. He is frequently called to give evidence before Parliamentary Committees.