David Cameron has promised to step up the pace of change in the Conservative party, saying there is "a mountain still to climb" in making it electable.
In his summer message to party activists, the Witney MP said that while the Tories had their best local election results for 20 years in May, more needed to be done.
"We have set a clear political direction so that now people can begin to see the contours of the next Conservative government - more green, more local, more family-friendly, less arrogant about politicians' ability to solve every problem," he said.
But Mr Cameron added: "We need to be ready for the general election whenever it comes. That means the changes we have to make must go faster, wider and deeper."
His comments come as a new poll finds that although the party continues to gather more support than Labour, confidence in his abilities as leader has fallen.
Yesterday, Lord Tebbit warned that Mr Cameron's attempts to introduce 'modern, compassionate Conservatism' were alienating core Tory voters - but then the party's advertising guru, Lord Bell, said all of his changes were simply cosmetic.
A YouGov poll in January found that 46 per cent of voters believed Mr Cameron was "proving a good leader" of the Tories, but in a similar survey today, this falls to 35 per cent.
Similarly, the percentage of people who believe he is not an effective leader rose from 19 per cent to 33 per cent over the same period, today's Daily Telegraph poll finds.
And while Mr Cameron is beating Tony Blair as the best prime minister, it is only by a very slight margin - 26 to 25 per cent. One in four respondents said they did not know.
The Tories are still in the overall lead, with 38 per cent of voters saying they would pick the party if a general election were held tomorrow. This is down one point on last month.
Labour, meanwhile, remains unchanged on 33 per cent in today's poll, while the Liberal Democrats stay on 18 per cent.
However, the Conservatives' support is below their target of 40 per cent, a level of support most analysts believe would give them a serious chance of winning the next general election.
They could also expect to be doing better given the series of scandals to hit the Labour government, including the cash for honours probe, the blunders at the Home Office and John Prescott's antics.
"I believe that by working together over the past seven months, we have become the powerful new voice for change, optimism and hope in our country," Mr Cameron said.
He added: "The Gordon Brown approach to government - top-down, centralising, with a state solution for every problem - has clearly failed. Labour's shambolic performance since the last election has destroyed people's faith that the state can deliver.
"Our responsibility is to provide an exciting, competent and credible alternative."