It all started so innocently. I wanted to write a book about the first Labour Chancellor of the Exchequer for two decades. I knew him a little, and certainly admired him. Had he stood for the party leadership after John Smith's death in 1994, I would have voted for him rather than Margaret Beckett, whom, in the event, I did vote for. Brown is a real party man, who knows and understands the trade unions, which were my first love - politically speaking. I knew Charlie Whelan, Brown's press adviser, from the engineering union where he worked for the late Jimmy Airlie, hero of the Upper Clyde work-in of the early 1970s - an event that also fired Brown's imagination.
So I put it to Charlie Whelan in late 1996 that I should do the book. But I wouldn't do it without co-operation from Big Gordie. There were other bidders. I met Brown in his Westminster office, an octagonal stone pavilion where the death warrant of Charles I was signed. I argued that I had a track record as a biographer - Arthur Scargill, Betty Boothroyd and John Hume - and he knew he could trust me. Eventually, after what seemed an interminable time, a letter arrived on 17 February 1997 promising "full co-operation and full access to personal papers". He added: "On the basis that you intend that the book appears as soon as possible following Labour's first Budget I intend to co-operate with you."
And so he did, though the personal papers turned out to be chiefly a great pile of speeches about the economy. He also gave four extended interviews, two in his wood-panelled office in the Treasury, one at his home and another in an official car. He was adamant that he would not talk about his personal life - he is a very private man - or the leadership campaign that never was. For the latter he directed me to Nick Brown, the chief Whip, and for the former I turned to his brothers, John and Andrew, and his closest friends, Dr Colin Currie, an Edinburgh consultant; Bill Campbell, the Scots publisher; and Wilf Stevenson, the film industry administrator. Alex Falconer, MEP and former convenor at the Rosyth shipyard that was Brown's powerbase, was also particularly helpful, as was David Stoddart, his former constituency agent. There is no doubt that all of them, and more, were speaking with Brown's approval, though I have no way of telling whether they were giving me information that Brown wanted to make public or whether they were simply answering my questions.
Either way, I had a scoop on my hands. Gordon Brown had a deal with Tony Blair that they would not run against each other for the Labour leadership. The deal was that Gordon would be the candidate. But the smart metropolitan Labour set, most notably Alastair Campbell and Peter Mandelson, thought otherwise. While Brown was busy rewriting the party's economic policy to make it electable, they were promoting Blair's candidacy and they moved with lightning speed the day that John Smith died. Brown genuinely thought he could have won a leadership battle against the "upper class, public school educated" Blair, but he stood aside to avoid damaging the modernisation project. He still believes he could have won, and might yet do so if and when the opportunity presents itself. He will go, as he remarked to me, "as far as I can". In an interview with Steve Richards in the New Statesman on Friday, Brown was asked if he still wanted to be leader of the Labour Party at some point in the future. "That's a matter for the Labour Party," he replied. "I've got a lot to do here." Richards assumed that meant yes. It is a safe assumption.
The hungry political editors accompanying the prime minister in Tokyo last weekend lapped up the speculation. It was more fun than the Japanese almost-apology to British PoWs. Blair's entourage was furious. The Sun yelled that Brown had sanctioned "a bombshell book" that exposed splits at the heart of Downing Street. It "sensationally" claimed that Brown blames Blair's aides for a smear campaign about his private life. Well, his friends most certainly do. The newspapers were full of headlines about Brown wanting Blair's job. That this should come as a surprise to anybody is an interesting commentary on political journalism.
From my less high-profile position, the heat was on at Westminster to "prove" that the book was "authorised" and therefore a deliberate leak by Brown to destabilise the Prime Minister. It was open season on the writer. A BBC radio source claimed that the premature sale of the book at Glasgow airport to George Galloway, Labour MP for Hillhead, and its subsequent leak to the pseudo-revolutionary public schoolboy Seumas Milne of the Guardian was all a put-up job to generate pre-publication publicity. In fact, I have written apologies from the publishers and John Menzies for their appalling incompetence, which allowed the book's enemies to get their retaliation in first. I was dismissed as a "London sophisticate" in the Spectator, which will come as something of a surprise to my stylish friends in public relations, who regard my social life as something rather closer to the farmyard. The Daily Mail preposterously described me as "one of Brown's closest friends" who had "conjured up" - ie fabricated - Brown's relationships with women. This crude attempt to revive the gay smear against him - which has been peddled by two ministers, one of them in the Cabinet - was particularly nasty. I was so rude to the writer that I had to apologise. The barrage of insistent telephone calls was so intense I took refuge in the Lords' Bar, which is off the beaten track. But the Sun tracked me down there, sniffing around for quotes that would damage Brown. For the record, the book is not authorised. I don't write authorised biographies, and I am nobody's spokesman. The extent of Brown's co-operation may be judged from the context.
Beguiling comparisons have been drawn with Andrew Morton's Diana, Her True Story, which was eventually revealed to have been inspired by the princess. In my dreams! It would be very pleasing to think that a book about a Chancellor of the Exchequer famed - quite wrongly - for his dourness would make me a millionaire, but it isn't going to happen.
Where does the whole episode leave relations between Brown and Blair? Pretty much the way they were, according to the Chancellor's close aides. If the Prime Minister is irritated, he did not show it in an hour-long telephone conversation on Friday morning. "Tony isn't over the moon," said a senior government source, "but there is no way it will affect his relationship with Gordon. It is an intellectual relationship." Brown's view is also clear from the New Statesman interview. "I think it's quite wrong to say this is me trying to do certain things. The friendship between Tony Blair and me has been very strong over the years and has had to withstand all sorts of press speculation," he said.
Some of the Prime Minister's close advisers are less able to take a calm view. Indeed, there has been an unpleasant whiff of the police state about the events of the last few days. While I was attending - as an invited guest - the wedding of Brown's economics adviser Ed Balls to Yvette Cooper MP yesterday week in Eastbourne, aides of Tony Blair were ringing the Prime Minister's office in Tokyo to tell them that I was there and who I was talking to. Clearly, the control freaks in this government never relax, which does not bode well for political biographers. There are more books to come; John Kampfner on Foreign Secretary Robin Cook, and the Independent's Donald Macintyre on Peter Mandelson, the Minister without Portfolio. My next book will have "unauthorised" on the front cover, to make sure this farce will not be repeated. And I will never again doubt the genuineness of people unexpectedly thrust into the limelight who say they want to be left alone.