If he maintains this Stakhanovite work-rate, Dominic Sandbrook will have written the definitive, 8,000-page history of Britain’s post-Churchillian twentieth century by the time he is 44 years old. This would be no mean achievement and he is showing no sign of exhaustion in this, his fourth volume. Seasons in the Sun begins with Mr Wilson entering Downing Street for the second time and concludes with Mrs Thatcher reciting Francis of Assisi. The intervening five years were so bleak, bizarre and tragicomic that they seem to come from another planet. If there is a criticism of this book it is that the phrase ‘almost unbelievably’ is used rather too frequently, and yet how else does one preface tales of a prime minister so paranoid that he takes to holding meetings in his private lavatory, with all taps running, for fear of espionage? How else to describe the Jeremy Thorpe case, or the outbursts of Marcia Williams, or Ted Heath’s thirty-year sulk, let alone trade unions demanding wages rises north of sixty per cent?

More heavily focused on politics than previous volumes, the book finds the champions of the post-war consensus finally running out of the other people’s money. Even by the standards of the 1970s, the years of the second Wilson government (1974-76) were unremittingly grim. Sandbrook’s history of the 1960s provided a valuable service by reminding us that only a small part of London was swinging. Despite his best efforts, popular perception of that decade is destined to be forever informed by the memories of a small elite, but if the history of the sixties has largely been (re)written by the winners, there is a danger of the seventies being re-imagined by the losers. A few years ago, the New Economics Foundation declared 1976 to be the UK’s happiest year since the war but, as Sandbrook remarks, the think tank must have used a strange index because the diaries and letters of those who lived through it are soaked in the darkest pessimism. Sure enough, the New Economics Foundation prioritised income equality, resource depletion and ‘public sector investment’ as measures of well-being, but these were little valued in an era of stagflation, IRA atrocities and endless industrial action.

Elected as the candidate most likely to placate the unions, good old Mr Wilson capitulated at every turn but ultimately failed to prop up Keynesianism, leaving office with government spending at fifty per cent of GDP, inflation at thirty per cent, house prices in their third successive year of decline and sterling falling like a stone. ‘If I were a younger man’, said his successor James Callaghan, ‘I would emigrate.’ Many did. The Rolling Stones, John Lennon, David Bowie, Michael Caine and countless other stars of the stage and screen moved abroad to escape the 83 per cent top rate of income tax. (In doing so, they helped to reduce inequality in Britain which must count as some sort of pyrrhic victory for the left). For those who remained, including Roy Strong, Kenneth Williams, Philip Larkin and Alan Clark, the only question was whether the country would swing to the far-left or the far-right when Britain finally and inevitably collapsed.

Seasons in the Sun captures these gloomy times brilliantly, but Sandbrook’s ability to find humour in the most unlikely places means that the gloom never suffocates the reader. Some events, such as Ally MacLeod’s doomed attempt to lead Scotland to World Cup glory and Anthony Wedgwood Benn’s proletarian pretensions, are inherently amusing. Others, such as the Birmingham pub bombings and the Yorkshire Ripper’s reign of terror, are clearly not. Sandbrook weaves them all together with pertinent references to popular culture. ‘It’s bloody Wilson!’ screams Basil Fawlty when he finds his fire extinguisher to be defective, while Reginald Perrin’s friend prepares a vigilante war against ‘Communists, Maoists, Trotskyists, neo-Trotskyists, crypto-Trotskyists, union leaders, Communist union leaders, atheists, agnostics, long-haired weirdos, short-haired weirdos’ and many more.

It is difficult to argue with Sandbrook’s assessment of Wilson’s second administration as the worst in living memory. It was certainly the most peculiar, with the prime minister a shadow of his former self, making weak and lamentable decisions such as bailing out Chrysler soon after bailing out its equally hopeless competitor British Leyland (this, presumably, counts as ‘public sector investment’.) Callaghan’s government, however, is portrayed as a significant improvement, led by a decent man dedicated to fighting the cancer of inflation. Admittedly, it took the humiliation of a £3.9 billion loan from the IMF to bring the government to its senses, but Sandbrook gives Callaghan and Healey due credit for seeking a way out of the woods. The latter reflected that his government had ‘buggered around with industry more than any country in the world’, while Sunny Jim’s admission at the 1976 Labour Party conference that government could not spend its way out of recession signalled that a lesson had been learnt (alas, it has since been unlearnt).

Ultimately, Sandbrook argues, Callaghan’s attempts to stop the rot were thwarted by the trade unions at the decisive moment in 1978-79, having received insufficient support from a Labour Party that was increasingly dominated by what Bernard Donoghue called ‘middle-class left-wing neurotics’. Tony Benn, who held a job in government throughout these years despite his breath-taking disloyalty, crystallised the fantasy economics of the time when he warned that it was ‘a dangerous doctrine’ for government to consider the profitability of a company before spending taxpayers’ money keeping it afloat. That such delusional thinking was not only commonplace, but had been largely accepted by politicians for years was, as Sandbrook might say, almost unbelievable. Seasons in the Sun is the story of chickens finally coming home to roost and is an antidote to the popular view of the decade as an era of space-hoppers, disco and kitsch. It should be read by anyone those who thinks 1976 was the best year ever.