Ex-Tory leadership contender Ken Clarke has said there would have been a "blood bath" if he had tried to push through the changes made by David Cameron.
Ken Clarke is heading one of Mr Cameron's task forces
Mr Cameron has urged the party not to be afraid of the pace of his reforms.
Former chancellor Mr Clarke said: "I would have been wading through blood by now, trying to get the party to where David Cameron has got it."
Mr Clarke told The Independent the Tory leader had benefited from being a fresh face who had "no baggage".
There have been rumblings from some Conservative right-wingers who believe Mr Cameron has taken the party too far to the centre ground, aping New Labour.
The new Tory leader has put more emphasis on issues such as social justice and the environment, arguing the party should be prepared to stand up to business and put economic stability ahead of tax cuts.
Mr Clarke told The Independent Mr Cameron was doing "extremely well" in persuading the Tories to accept change and showing voters the party is adopting a different set of principles.
The ex-minister said he would have wanted to do the same if he had won last year's leadership election.
"I always realised that if I became leader, it would have been a huge test of my political skills to avoid a civil war," said Mr Clarke.
"I would have had to come to terms with the right more than David has had to.
"I would probably have had to have more right-wingers in the shadow cabinet. I would have had to be more cautious than he has, so he has advantages."
'Commit to change'
Mr Cameron has put Mr Clarke in charge of the party's democracy task force, which is charged with finding ways of giving Parliament more power and restoring public trust in politics.
There would be better government if Cabinet decision making was restored and ministers listened to civil servants, said Mr Clarke.
He wants to get future Tory ministers to "put themselves in chains and commit themselves to changing the system", he said.
More people would vote if the quality of the national political process was improved, he argued.
"The politicians are as guilty as the media for turning it into a rather lightweight soap opera - the awful Clintonesque techniques, the focus groups, everyone chasing the same voters with the same slogans and clichés," he said.
Asked if Mr Cameron had a presidential style like Tony Blair, Mr Clarke said the Tory leader was still in his "honeymoon" period and hoped he would "bring on" other shadow ministers.
"A successful opposition needs four or five recognisable figures," he said, arguing that Mr Cameron should not fight the next election as a "one man band".