One of Tony Blair's most senior policy aides is quitting Downing Street for a top job in the National Health Service, in the latest departure from the prime minister's inner circle.

Paul Corrigan, who has served as Mr Blair's adviser on health since 2005, is leaving to become director of strategy and commissioning for the NHS in London. He has been one of the main proponents of the government's market-based reforms and his appointment presages a further shake-up of health services in London.