Just as the first cuckoos welcome spring, so the first newspaper serialisations of political memoirs herald the party conference season, with its fetid brew of intrigue, rebellion at the fringes and dead-eyed choreography on the central stage. This year, the first claimant upon posterity’s favour is Ed Balls, who – while preparing for his appearance on Strictly Come Dancing – has been finishing off a political autobiography, Speaking Out. (Was he ever tempted to rename it Strictly Speaking? Just a thought.)

The former shadow chancellor and close lieutenant to Gordon Brown has long been a divisive figure: when I was editor of the Spectator, a prominent Blairite offered me a piece on the theme “Why Ed Balls is to blame for all of Labour’s problems” (the outraged Friend of Tony withdrew the offer after he had calmed down). At any rate, when Balls lost his Morley and Outwood seat last year, there was plenty of crowing among his notional comrades.

Curiously enough, however, a surprising proportion of those who disagree with Balls ideologically concede that he is a warm and stimulating companion. He never hit it off with David Cameron but got on well with George Osborne (I have heard both men say independently that they enjoy going for a drink together: intellect is a powerful adhesive).

So I have high hopes for the Book of Balls, which will compete this autumn with memoirs by Ken Clarke and Sir Malcolm Rifkind, and the forthcoming account of the EU referendum campaign by Cameron’s communications chief, Sir Craig Oliver. Certainly, the extracts published thus far by the Times, accompanied by a lengthy interview, have been an evocative reminiscence of an age that already feels long gone.

Through the author’s eyes, we are back in the world of Brown, Peter Mandelson’s sensational resignation in 1998, IMF summits in Hong Kong, a 7am meeting in Helsinki in 1999 at which Balls “arrived to find Tony in a white dressing gown, and Gordon in his full suit, as tended to be their way”. These were Labour’s rollercoaster years in office, during which the party far exceeded its electoral success in the past, winning three successive terms with substantial majorities (two of them huge).

As even the Tories had to acknowledge, it had become a serious party of government, its upper echelons populated by serious and weighty figures. It is extraordinary to reflect that this era in Labour’s history ended only six years ago, and to consider how much has changed since Brown left Downing Street. As Balls says of Jeremy Corbyn: “If you are the kind of person who feels that you are succeeding when you have a rally of your supporters cheering you, well, that’s not my conception of politics. My conception of politics is that you succeed when sceptical centre-ground voters decide to trust you more than the other side.” Until Labour grasps that Balls is right and Corbyn is wrong, it will remain an intermittently distracting sideshow, confusing its impotent anger for fiery relevance.

All the same, nostalgia is the foe of objective analysis: as depressing as it is to observe the decline of Labour from a mighty party of power to a pious protest movement, a candid chronicler of that transformation will detect many of its roots in the conduct of New Labour’s oligarchs and their acolytes between Blair’s leadership victory in 1994 and the defeat of Ed Miliband in 2015.

Of course, Balls was a key figure in Labour’s most electorally glorious epoch. But that epoch also set the stage for what has happened since. During the 1990s the party’s elite drained power from Labour’s traditional structures and centralised all significant authority in the leader and his or her entourage. Yet even as the party’s oligarchs preached the virtues of discipline to the mass membership, they themselves fought one another with shameless ferocity. First it was Blair and Brown; then Brown and David Miliband (of whom Balls says: “In the end, I don’t think David had the political tenacity”); then the two Eds, leader and shadow chancellor. Balls claims – astonishingly – that he and Miliband had only two proper conversations during the 2015 election campaign. He also recalls his resentment that “regularly from 2010 onwards there would be briefings from his team against me, about me being sacked. Every time I would see him he would be very upset about it, but it never seemed to stop happening.” If ever there were a textbook example of Freud’s “narcissism of small differences”, it was this relentless tendency of Labour’s elite between 1994 and 2015 to split into two warring factions.

Corbynism, with its implacable emphasis upon the party-as-movement and the role of the rank and file, was the inevitable reaction to the structural revolution that began in 1994 and to its pathologies. Iraq, the leadership’s bid to have it both ways over Osborne’s austerity programme, the loss of Scotland to the SNP, the party elite’s shameless in-fighting: all this was the backdrop to the grassroots rebellion that secured the leadership for Corbyn last year, and will probably do so once again in his current contest with Owen Smith.

Important as Labour’s destiny is, it is eclipsed by the future of the country. I suspect this autumn’s haul of political books will be remembered predominantly for what they disclose about Brexit, its causes and its aftermath. In which respect, Balls makes two related claims: first, that the “personalisation” of the vote around Cameron’s character was “a catastrophe”. Second, he believes that the remain campaign in the EU referendum needed a counterpart to Brown’s promise to the Scots in 2014 of more reform if they voted to stay in the union: the so-called vow.

According to Balls, the UK electorate should have been promised more than the status quo, modified by Cameron’s “renegotiation” of Britain’s terms of membership. They should have been promised a rolling process of reform – as at least one senior Tory recognised: “George [Osborne] said that he was very conscious of the status quo point and thought, like in Scotland, we would need to come back with a vow-style commitment to reform, including around immigration, in the final week or two.” Or, to translate: it wasn’t me or George, guv.

Two months have passed since Britain decided to leave the EU. Shock has given way to practical questions about the future and an audit of what, precisely, happened on 23 June. Listen carefully. Can you hear the engine of recrimination revving up? Round one – of many – to Balls.