Michael Portillo has slammed "stupid" Tory MPs who think the Conservatives would have been able to push through a more radical programme of reforms had they shunned coalition with the Lib Dems.
The former Tory defence secretary said the coalition had in fact given David Cameron the political cover necessary to pursue an agenda almost as transformative as Margaret Thatcher's.
"Cameron is leading a government voted for by 60% of population, instigating austerity measures almost equivalent to Thatcher's," Portillo said. "Welfare reforms she would never have dreamt of, education reforms she would never have touched and health reforms she never touched."
"He would never have had permission from the media to do these reforms if he was leading a minority government," he told BBC's This Week programme on Thursday evening.
And he attacked the "stupid blinkered Tories" who think Cameron is constrained by leading a coalition. "Actually he has been liberated by coalition to do vastly more than he could ever achieve leading a minority."
Looking forward to the next election Portillo said "the Conservatives appear to be doomed" because no political party has increased its share of the vote while in government since 1955.
Several Tory MPs frequently blame the Lib Dems for blocking more radical Tory policies from being put in place, with some even calling for the coalition to be broken up immediately.
Backbencher Peter Bone has argued it is "not the prime minister’s fault but our Liberal Democrat partners that we are producing wishy-washy, irrelevant policies".
"A Conservative minority government with real Conservative policies would lead to people not resigning from the party but joining in droves," he said.