The 2003 Conservative Party leadership election was held due to the enforced resignation of incumbent leader Iain Duncan Smith, who lost a confidence vote among his parliamentary party. The causes of Duncan Smith's fall are often cited as his lack of charisma and impact with the public, the uninspired direction of the party under his leadership, and his previous failure to achieve more than a third of support among members of parliament in the 2001 leadership contest. In the event, the Conservative Party coalesced around Michael Howard as replacement leader and there was not a contest to replace Duncan Smith.

The 2001 Conservative Party leadership election was held after the party failed to make inroads into the Labour government's lead in the 2001 general election. Party leader William Hague resigned, and a leadership contest was called under new rules Hague had introduced. Five candidates came forward: Michael Ancram, David Davis, Kenneth Clarke, Iain Duncan Smith and Michael Portillo.