Former Croydon schoolboy Sir David Freud has quit his role as a senior Labour government advisor on welfare reform to work for the Tory party.

Sir David, 59, was working for Labour’s Work and Pensions Secretary James Purnell as an advisor but this week left his job to become a Tory spokesman in the Lords and join David Cameron's council of economic advisors.

It is rumoured to be Gordon Brown's continued opposition to Sir David’s welfare reforms plans which have sparked Freud's defection to the Tories.

From journalism to the city and now politics, the great-grandson of psychoanalyst Sigmund has led a colourful career.

Sir David said that he first knew he wanted to be a journalist when he was a 14-year-old boy at the Whitgift School, Croydon.

After he completed his degree at Oxford he ended up at the Financial Times "almost by accident".

From there he was headhunted in 1983 by Rowe & Pitman where he worked for 20 years before moving on to become an advisor responsible for putting together complex deals including the flotations of Eurotunnel and the financing of the Channel Tunnel rail link.

Despite blunders over the rail link, Tony Blair hired him to review the welfare system. In 2007 he proposed getting more lone parents and disabled people into work and to put long term unemployed training schemes in the hands of the private sector.

However, most of the suggestions in the Freud report were shelved amid reported opposition from Gordon Brown.