Michael Portillo has accused David Cameron of "losing his nerve" over his attempt to rebrand the Conservative Party.
The former cabinet minister, a Tory moderniser, who is normally supportive of Mr Cameron, said: "To change, you need to change the people at the heart of the party. He is trying, but it has not been as successful as he hoped."
His remarks scuppered the Tory leader's call for a period of silence from internal critics and highlighted his difficult balancing act as he tries to keep both wings of his party happy. Earlier this week, Michael Ancram, a traditionalist former deputy Tory leader, criticised Mr Cameron for "trashing" Margaret Thatcher's legacy.
According to Marketing Week magazine, Mr Portillo told a conference in Southampton that Mr Cameron knew he had not "succeeded sufficiently" in his efforts to change his party.
Further doubts were expressed by Kulveer Ranger, a Conservative Party vice-chairman, who urged Mr Cameron to shake off his image as a modern-day toff. He said: "He must battle to establish who he is and what he is. A toff with a conscience? A modern day social/eco warrior?"
The remarks overshadowed Mr Cameron's launch of a plan to create a six-week summer programme of charity work or physical training for all 16-year-olds.Although it would be voluntary, he did not rule out making it compulsory. He called it a "a 21st century version ofnational service" that would help build a stronger society and mark "a rite of passage" from youth to adulthood.
Meanwhile, Gordon Brown yesterday launched a review of children's policy and appealed to the public to help him write a new one. He told a "citizen's jury" of 50 teachers, pupils and parents in Bristol: "The old days of someone else making the policies and the people not being involved are over."Mr Brown added: "In the next 18 months we've got new plans for the Government and children's services. You cannot do that in the modern world if it is just someone sitting in Whitehall or in another government office planning these things. You can only do it by responding to the concerns and aspirations of people like you here today who've thought about these things and understand the problems."
The review will be headed by Dr Tanya Byron, a psychologist who appears in the BBC series Little Angels and House Of Tiny Tearaways. It will look at the impact of violent video games and internet pornography on children.
Dr Byron said: "The internet is a powerful and positive tool. However, we must all enable our children to use the internet in a way that is positive and safe."