A former shadow home secretary and shadow chancellor, Oliver Letwin is one of the most experienced and erudite members of David Cameron's top team, playing a key role in the formulation of the policies with which the Conservatives will fight the next general election.

An Old Etonian and former merchant banker, he has been MP for West Dorset since 1997.

In the 2001 election, he famously went into "hiding" after suggesting to a newspaper that the party wanted to cut public spending by £20bn.

After the 2005 general election, at the age of 50, he decided to take the environment, food and rural affairs brief before being handed the job of reviewing policy across the board and made chairman of the Conservative research department.