Key players in Tory leadership

With rumours of plots against Iain Duncan Smith's leadership intensifying, BBC News Online outlines the key players in the ongoing Tory troubles.

Iain Duncan Smith: Beset by sniping against him, Mr Duncan Smith says he has earned the right to be leader and will stay in his job until the next election.

Sir Michael Spicer: Chairman of the 1922 Committee, which represents all Tory backbenchers. Under party rules, 25 MPs can force a confidence vote in Mr Duncan Smith by writing to him. Sir Michael keeps any such letters secret, and would not announce that he has received any demands unless at least 25 MPs come forward.

David Maclean: Tory chief whip - the man in charge of making sure Tory MPs obey their leader. Mr Maclean has branded as "fantasy" suggestions that he has told Mr Duncan Smith that he has lost his MPs' confidence. But it is thought he discussed last Wednesday how to deal with the plots in a meeting with his leader and senior Tories.

Crispin Blunt: The former frontbencher called for a leadership challenge in May but local election gains ensured that call came to nothing. Mr Blunt has now reportedly written to a number of MPs repeating his call, saying: "We must act now to save our party from further decline." He has now confirmed he has written to Sir Michael Spicer asking for a confidence vote.

Derek Conway: The former Conservative Party whip this weekend became the first Tory MP to say publicly he had written a letter to Sir Michael asking for a confidence vote to be held. He claims that three quarters of Tory MPs believe Mr Duncan Smith "is not up to the job".

Sir Patrick Cormack: One of the first MPs to put his head above the parapet last week. A member of the 1922 Committee executive, Sir Patrick has urged Mr Duncan Smith to call a vote of confidence in himself to halt the ongoing leadership saga one way or the other.

Stuart Wheeler: The millionaire betting magnate, who gave £5m to the party at the last election, sparked the latest bout of speculation when he said there was an "overwhelming" case for replacing Mr Duncan Smith. However, former Tory treasurer Lord Ashcroft says most donors will continue their support.

Sir Philip Mawer: The parliamentary standards commissioner is investigating claims that Mr Duncan Smith employed his wife Betsy out of public money for work which did not justify her salary. The Tory leader says he will be cleared by the inquiry and if that happens, many commentators believe it will strengthen his position.