Mary Ann Sieghart profiles Iain Duncan Smith whose Work and Pensions Department will be hit during next week's Spending Review. His proposed welfare reforms have been described as 'the biggest since the war-time work of Beveridge' and a white paper is expected after the Spending Review.Iain Duncan Smith started out briefly in industry after leaving the army where he served twice in Northern Ireland. His father was a famous World War II flying ace & his mother a ballerina. In the 1990s, he was best-known as one of the Tory party's most strident euro-sceptic MPs. His short two year leadership of the Conservative party was mostly unsuccessful. The "quiet man" was unable to unite his party. But it was during this time that Iain Duncan Smith began to see the need for welfare reform. After he was ousted from the leadership he set up the Centre for Social Justice and is credited with forming much of David Cameron's social agenda. Mary Ann Sieghart talks to his political allies & foes, long-standing friends and the people who began to change his political direction. Producer : Rosamund Jones.