Today I have released details of the title and cover of my forthcoming biography of David Cameron – but the book won’t be published until the autumn.

Call Me Dave, the title of the book, will have to compete with another book about Cameron by the respected historian Anthony Seldon. He has a long track record of producing detailed tomes about modern prime ministers, usually with a great deal of help from the top. His forthcoming volume on Cameron at Number 10 will be no different.

I understand Seldon is rushing his book out to avoid a clash with mine. Apparently he is being encouraged to do so by Number 10. Having originally planned to publish during party conference season, I am told that he now intends to publish at the end of July. Number 10 is so eager to assist that aides have been reading and correcting draft chapters. It will be a pleasant surprise if his book is not merely a sanitised account.

Setting aside the wisdom of publishing a political book when even Westminster is tired of politics and packing up for summer recess, Seldon’s haste to “get in first” is curious. After all, we are not trying to do the same thing. Like a number of his previous books, his is an account of Cameron’s administration, which begins when the Tory leader takes office in May 2010. Mine is a life story. I do not intend to give a blow by blow account of what has been achieved in every Whitehall department, though of course I will take some account of policy delivery. However, my focus is on character: what made the man; how he got to the top; and how he used his power.

I have made it clear that my book, a collaboration with former Sunday Times Political Editor Isabel Oakeshott, will be objective. Nonetheless Cameron is suspicious. It is no secret that he dislikes the prospect of what he dismissively labels “the Ashcroft book”. We have tried, and failed, to persuade him to talk. While Seldon has had full co-operation from Number 10 (I am told “everybody” – from Ed Llewellyn, Cameron’s chief of staff, down – has been encouraged to make time for the historian) the Prime Minister has shut the doors to us. Letters to relatives requesting interviews have gone unanswered, and senior aides know he does not want them to help. Some individuals who were willing to talk to us in principle but wanted Downing Street’s blessing were repeatedly stonewalled. Cameron’s strategy appears to be: put up the shutters, then rubbish the book on the basis that we have had no access.

Happily, many of his friends and colleagues disagree with this approach. For all his disapproval, the vast majority of those we have approached have agreed to talk, including a number of Number 10 insiders who have assisted amid utmost secrecy. Some of those who like and admire the prime minister struggle to see the sense in blocking positive contributions.

Call Me Dave will be entertaining, revelatory and insightful. The prime minister may not like some things, but I hope he will acknowledge that it is fair. It is intended to be. It will be published this autumn. We eagerly await Seldon’s account, and will incorporate, where relevant, any interesting highlights. Meanwhile, follow this link to order a copy of Call Me Dave – the unauthorised biography of David Cameron.