Blunt hurls fresh criticism at Tory leader and urges MPs to oust him

A senior Tory MP has urged his colleagues to rise up in mutiny against Iain Duncan Smith before the inquiry is completed into the salary received by the Conservative leader's wife.

In a letter sent to fellow Tory MPs last night, Crispin Blunt said the Conservative Party faced "further decline" under Mr Duncan Smith and warned that delaying a putsch could be a mistake because the investigation could strengthen the Tory leader's position.

Mr Blunt resigned from the Opposition front bench in May to call for the party to ditch Mr Duncan Smith. But he was left isolated when the Tories won more than 550 seats in the local elections on the same day, bolstering the leader. His letter, leaked to The Independent, said that he accepted the party had given Mr Duncan Smith a vote of confidence after the May elections. But he argued that had been "rendered valueless for the party and Iain" by this month's Tory conference in Blackpool, which was overshadowed by internal criticism of the leader.

Mr Blunt, MP for Reigate, added: "I believe the party is at a moment of strategic opportunity and danger ... If I didn't believe with every instinct that we must act now to save our party from further decline, that we do have an opportunity to return our party to power and that this is absolutely in the country's interest then I would do nothing. It is after all the easiest course."

Tory MPs who want to topple Mr Duncan Smith are divided over whether to delay their move until the investigation by Sir Philip Mawer is completed. The parliamentary standards commissioner is looking into Betsy Duncan Smith's salary for acting as her husband's secretary.

Mr Blunt's move may encourage more Tory MPs to write to Sir Michael Spicer, chairman of the 1922 Committee, calling for a formal vote of confidence in the party leader. Twenty-five names are needed to trigger such a vote and it is believed that more than 10 have already done so, including Mr Blunt.