Professor Alexander has served as an adviser to the British Government and the European Parliament's Economic and Monetary Affairs Committee. He is a Member of the European Parliament's Expert Panel on Financial Services. In August 2011, he was appointed Specialist Adviser to the UK Parliamentary Joint Select Committee on the Financial Services Bill 2012.
In 2008 and 2009, he gave oral and written evidence on several occasions to the House of Commons Treasury Committee and the House of Lords Select Committee on Economic Affairs on UK and European financial legislation and regulation. In July 2006 he gave oral and written evidence to the House of Lords Select Committee on Economic Affairs on the "The Impact of Economic Sanctions"; and in November 2006 was invited to give oral and written evidence to the European Parliament's Special Committee on 'the Crisis at the Equitable Life Assurance Society'.
Since the 1990s, he has advised central banks and national banking and securities regulators in both developed and developing countries on issues related to prudential regulation of banking and securities markets.