The Conservatives are only half way towards winning a general election, party chairman Francis Maude has admitted.
He issued the gloomy prognosis during a visit to Birmingham, even though the Tories enjoy a ten-point lead in the opinion polls.
Speaking to The Birmingham Post, he said: "We have had a terrific start in David Cameron's first six months as leader but we have a long way further to go."
Mr Maude was in the city to meet Tory activists as part of a roadshow explaining Mr Cameron's plans to modernise the Conservative Party.
The Tory leadership is trying to win over grass-roots members to its plans for a "modern, compassionate Conservative Party" which can be a voice for "change, optimism and hope".
This has meant drawing up a list of principles which downplay the importance of cutting taxes.
Mr Maude admitted there had been some resistance to the changes in the party.
He said: "Some of these things have raised some eyebrows among traditional conservatives, and not everyone has bought in to it.
"But we are making the case. We are showing why we think the changes are needed.
He added: "In recent years we have been seen as being backward looking.
"We have lost three general elections in a row. That means we are not able to do what the Conservative Party ought to do, which is to serve our country in Government."
A poll earlier this month placed the Conservatives on 41 per cent of the vote with Labour on 31 per cent.
But asked how much more the party had to do before it could win a General Election, Mr Maude said: "We are probably about half way there."
He was heartened by the party's success in May's local elections in Birmingham, he said.
Mr Cameron also announced yesterday that he had appointed city MP Andrew Mitchell as shadow Minister for Birmingham.
The Tories are appointing members of the shadow Cabinet to represent the party in every major city of Britain, in a bid to boost the party's popularity in urban areas.
Mr Mitchell, Tory MP for Sutton Coldfield, will take responsibility for improving organisation in the city.
He will also advise colleagues in places like Liverpool and Newcastle, where the party has no MPs and almost no presence on local councils, on how Conservatives can start winning again in Britain's inner cities.
Mr Mitchell said: "I look forward to this exciting new responsibility as Shadow Minister for Birmingham.
"As a local MP, I know how much the region has to offer and how great its people are.
"Birmingham has suffered as have other cities in Britain from too much London-centric decision making. The next Conservative Government will tackle this head on."
Mr Cameron has put tackling poverty in the developing world and improving "quality of life" among his top priorities.
He also said he wants to get more black and female Tory MPs.
Publicity material distributed to party activists includes a commitment to ending poverty in the developing world, and stresses the need to improve "quality of life".