The Conservative Party has been thrown into turmoil after a senior MP warned it could never win under the current leadership.

As the local election results came in on Thursday night Tory frontbencher Crispin Blunt called on Iain Duncan Smith to resign.

Blunt quit the shadow ministerial team after warning that Duncan Smith would never lead the party to victory.

Launching a blistering attack which threatened to overshadow the local and devolved elections, Blunt said the Tory leader should resign "in the wider interests of the party".

"Whatever the headline results in today's local elections the fact is the Conservative Party is making no real progress when we should be taking advantage of the opportunity our opponents and events have offered," he said.

"If the electorate perceived us as a credible alternative government the potential support for us could carry us back to government.

"However we carry the handicap of a leader whom Conservatives in parliament and outside feel unable to present to the electorate as a credible alternative prime minister."

Blunt, leaving his job as a trade and industry spokesman, said Duncan Smith had "not made the necessary impact" and should go.

"If we are a political party that is serious about regaining power, our leader has to now be replaced," said the MP in a statement. "I hoped the leader could recognise this analysis himself."

Blunt said he hoped that 25 MPs would come forward to trigger a leadership election.

The intervention sparked a fresh round of speculation about the future leadership of the party.

Senior Tories rallied behind Duncan Smith following the latest attack on his leadership.

Conservative chairman Theresa May said party workers "would feel very let down" by Blunt's actions.

Oliver Letwin said the Reigate MP was "a one off" who did not speak for the parliamentary party.

"We are unlikely to win elections if we change leaders every week. I think Iain will stay as leader and I profoundly hope he will," the shadow home secretary said.

Tim Yeo, the shadow trade and industry secretary, said: "I don't believe there is a threat to the leadership."

Labour was quick to exploit the latest bout of Tory bloodletting.

Commons leader John Reid said: "Tonight is both a temporary disaster for them and a set back but it is also symptomatic of a much deeper malaise in the Conservative Party itself which is becoming incapable of being led."

Lib Dem party chairman Mark Oaten said: "The knives are out before the results of local elections are even in."