John is a Non-executive Director and Vice Chair of Marshall of Cambridge (Holdings) Ltd, an engineering and property company, and of ICE Benchmark Administration, which publishes financial benchmarks.
He is also a senior adviser to XMS Capital, a Chicago-based investment bank, and an investor in several fintech companies. He is a Development Fellow of University College, Oxford, a mentor to postgraduate students at Oxford University's Blavatnik School of Government and a co-author of "Public Net Worth: Accounting, Government and Democracy", a 2024 book about public finances.
John began his career as a civil servant at HM Treasury in the mid-1980s before joining Morgan Stanley, where he worked as an investment banker in London, New York and Hong Kong. In 2005 to 2007 he was seconded back to HM Treasury as its Senior Corporate Finance Adviser, and from 2008 to 2010 was Head of Market Investments at the Treasury's UKFI subsidiary, responsible for the government’s investments in Lloyds Banking Group and RBS (now NatWest). From 2010 to 2016 he worked in senior roles in HSBC’s investment banking business.
John was born and brought up in Cambridge and since 2016 has lived in south Cambridgeshire.