He will become chairman of the risk committee at Barclays UK.
As an independent member of the Prudential Regulation Committee, he had responsibility for many of the rules which will be applicable in his new role.
Following the 2008 crash banks were obliged to segregate retail and investment banking activities, the principal recommendation of Sir John Vickers’ Independent Commission on Banking.
Mr Thorburn’s recruitment completes the board line-up of Barclays’ ring-fenced unit which will house its retail banking activities and some of the products and services it provides to smaller business customers.
The chairman of the UK bank, Sir Ian Cheshire, said Mr Thorburn’s understanding of financial services, breadth of experience, and proven track record will make him an invaluable member of the new board.
Mr Thorburn headed the Clydesdale and Yorkshire banks for four years, stepping down in 2015 ahead of its flotation.