The end of the year is a time to look back and wonder about the selectivity of memory. If you keep a diary, this is when you re-read it, with that mixture of familiarity and strangeness. Some things that happened over the past year feel as if they did so only yesterday; others seem to belong to history.
And if you are in politics, even as second bag carrier to the assistant to the top banana, you can publish your diary and we can all experience that curious sensation about public people and national events.
If someone gave you a copy of The Hugo Young Papers for Christmas, you will find a fine example there. Young, the Grand Old Man of The Guardian, recorded a lunch with Alan Duncan, the Conservative shadow minister, in 1998. At that time, at the height of Tony Blair's popularity, Duncan was vitriolic about him.
"He regards Blair as a deeply evil man, a poseur, a power-mad centraliser, a serial liar at Prime Minister's Questions, someone who is perhaps the worst man ever to have risen high in British politics," Young recorded. That wasn't what Duncan was saying by the time Blair left office, come which point many Tories claimed him as one of their own. "We had to force ourselves to hate him," Duncan said recently. So when he says, as he did a couple of months ago, "Brown is the most deceiving politician I have ever met other than Ed Balls; they are performing the most revolting political gymnastics and we will nail it," we should perhaps take it as an interim assessment.
Like most recent prime ministers, Gordon Brown does not keep a diary. If he did, he would not want to re-read much of this year's record. Already, the misery of the first three-quarters of it, when he seemed destined to be remembered as one of the least successful holders of his office, has been foreshortened by perspective of the rear-view mirror. The "we not only saved the world" phase of the last quarter has wiped the memory banks.
Historians of the future may struggle to recapture the sense of a government on the edge of a nervous breakdown, as most of Westminster's press corps crowded into what would have been a routine news conference held by the Foreign Secretary and his Italian counterpart at the end of July.
I hope that some of the Cabinet are keeping diaries so that we can make sense of it later. It was interesting that Alistair Darling protested over the summer that "of course" he could stand up to Gordon, and that they had arguments, but that we would have to "wait for the memoirs to find out what they were about". Not the official papers, note, but the memoirs.
The practice of taking down what people say in confidence and publishing it while it is still sensitive enough to earn a lot of money has been one of the running controversies of the New Labour years. It is a recurring theme of the course on the Blair government that I teach with Jon Davis in Peter Hennessy's history department at Queen Mary, University of London. As contemporary historians, we are of course grateful for the breaking of old conventions, such as the 30-year rule, which is currently being reviewed – one of Gordon Brown's better jokes – by Paul Dacre, editor of the Daily Mail.
We agree with Peggy Noonan, the great speechwriter and memoirist of the Reagan presidency, who commented on the kerfuffle over the memoir published this year by Scott McClellan, who was George Bush's press secretary: "History needs data, detail, portraits, information; it needs eyewitness. 'I was there, this is what I saw.' History will sift through, consider and try in its own way to produce something approximating truth. In that sense one should always say of memoirs of those who hold or have held power: More, please."
Yet there is a problem here. Sir Gus O'Donnell, Britain's top civil servant, disclosed that he had written a letter to Alastair Campbell, Blair's former press secretary, telling him that it would be "wrong" for him to publish his diaries. But he could not stop them, and they hit the bookshops 12 days after Blair left office. "That was the reality," Sir Gus said.
Nor is this just a matter of a civil servant resenting the different culture of political appointees. Anji Hunter was, like Campbell, a special adviser in No 10, but said in July this year: "I don't want to write a book like that, and frankly I don't think you should. I belonged to a group of people who were, for a time, in a position of great influence and I don't think it's right. Besides, all those autobiographies – Alastair's, Lord Levy's, Cherie's and even Jonathan Powell's – have a common theme which is 'If it wasn't for me none of it would have happened'. I don't want to go down that route. The press are only interested in the salacious details, which often obscure what you might be trying to say."
It was only a couple of months later that Adam Boulton, Anji Hunter's husband and the political editor of Sky News, published his memoir of the Blair years, which contained the salacious details of, among other things, a "kangaroo court" to which Hunter had been summoned by Cherie Blair.
Obviously it makes it difficult to conduct effective government if ministers think that people are keeping notes and might make them public at any time. That was an issue when Barbara Castle scribbled away in her journalist's shorthand at Cabinet meetings in the 1970s. But now the pressures of expensive serialisations (Alastair Campbell is supposed to have turned down a six-figure sum for his) on one side, and Freedom of Information requests on the other, have created a quite different climate. Different, but mostly better.
Writing a diary is an oxymoronic pursuit. Private, yet self-glorifying. Eye-witness, yet unreliable. A chore to write, and often a joy to read. I got out of the habit when I was working on a biography of Blair – keeping track of his daily life was enough without keeping track of my own. But I want everyone in public life to do it. Ultimately, I am with Peggy Noonan: More, please.
John Rentoul is chief political commentator for The Independent on Sunday and visiting fellow at Queen Mary, University of London