Cameron braced for attack as Ashcroft sharpens his pen

At Prime Minister's Questions, David Cameron had fun gloating over the problems that memoirs like those of Lord Mandelson are causing the Labour Party. But he may not be laughing for long, because there is a book in preparation by a very senior Conservative which is expected to lay bare some of the simmering tension inside the Conservative Party.

Lord Ashcroft, the billionaire who bankrolled the Tories when their political fortunes were at their lowest, is still Deputy Chairman of the Conservative Party, although he has fallen out with David Cameron and no one in the higher ranks of the party seems to know what his long term plans are.

He has also been working on a book, which other Tories refer to as "Smell the Coffee Two". Though that is not its official title, Lord Ashcroft will be hoping that it could have an impact similar to the book Smell the Coffee, which he published after the 2005 election.

That book was based on the findings of tracker polls that Lord Ashcroft commissioned during the election, testing the attitudes of 10,000 voters, which delved into how the Tory party lost touch with the people whose support it needed. The book brought Lord Ashcroft back to the centre of Conservative politics. He wielded huge influence during 1997-2001, when William Hague was party leader, for the simple reason that it was Ashcroft's wealth keeping the party together, but he was less influential after 2001 though he still gave generously. Between February 2003 and December 2009, he is known to have donated £5.1m to the party.

Impressed by Ashcroft's analysis of why the Tories lost, Mr Cameron appointed him Deputy Chairman, with an office at party headquarters, and put him in charge of Tory strategy in the marginal constituencies.

But their relations nose dived in March this year, when the peer finally disclosed that he was a non-dom, which meant he paid no UK taxes on his overseas earnings. This revelation sat uneasily with the promise that he had made when William Hague recommended him for a peerage 10 years earlier, that he would become fully resident in the UK before he took his seat.

He now has a potential rival in the financier David Rowland, who is due to take up the post of Tory party treasurer in October. Days after he was appointed, Mr Rowland discovered how treacherous internal Conservative politics can be, when the Daily Mail ran an article attacking the business past of "the former tax exile who's the new Tory Treasurer", which is thought to have been inspired by a tip-off from within party headquarters.

Lord Ashcroft is said to be determined to retain an influential role in UK politics. One ambition is to become a media mogul by building up an online presence. He has bought into the websites Conservative Home and Politics Home.

This month, he formally gave up his non-dom status, after a law passed by the Labour government came into effect which confronted non-dom peers with the choice of resigning their seats or being taxed as UK citizens. And he has a line of communication to Downing Street through one of his former aides, Stephen Gilbert, who is David Cameron's political secretary.

He has also delayed publication of "Smell the Coffee Two", which he is co-writing with Kevin Culwick, a former party official. The book is expected to be critical of David Cameron's handling of the election campaign and his decision to go into a coalition with the Liberal Democrats. Interviewed on the night of the general election, Lord Ashcroft appeared to blame the failure to secure an outright win on Mr Cameron's decision to agree to participate in live television debates with Nick Clegg and Gordon Brown. One upshot of the coalition is that he finds himself on the same side as Lord Oakeshott, the Liberal democrat peer who pursued him relentlessly over his tax status. "He is having to sit on the same benches as his nemesis, and he really hates that," one Tory claimed.

The 64-year-old grew up in Belize, where his father was posted as a diplomat, and founded his huge fortune there during the 1980s. His website notes: "If home is where the heart is, then Belize is my home."

Despite the change in government, he is getting nowhere with his campaign to persuade the British government to increase its military presence in Belize, which is trapped in a border dispute with its larger neighbour, Guatemala. In an answer to a question from Lord Ashcroft, the defence minister, Lord Astor of Hever, warned him to expect disappointment. "The Ministry of Defence is facing significant financial pressures and we must... focus our resources on our key areas," he wrote.

The answer can hardly have come as a surprise when the defence department is facing budget cuts of up to 20 per cent, but it is a small sign of the billionaire's diminishing influence in the Tory Party. "Ashcroft definitely wants a role, but he isn't quite sure yet what role," one Tory insider said.