There has been a sad decline from then till now, and worse is aye in store. One of the main reasons that we can allow ourselves to rebelieve this story over and over again is our forgetting of how things have been. And then someone comes along and makes you remember . . .

“Throughout the Seventies,” begins Francis Wheen, “there was a rising hubbub of discontent, a swelling chorus of voices saying it couldn’t go on like this — whether ‘it’ was a sclerotic Soviet bureaucracy, a jackbooted Latin American dictatorship, an enfeebled British corporatist democracy, or merely the quotidian headache of trying to make a phone call without a mechanical chorus of clicks, wheezes, and crossed lines, as of a thousand boiled sweets being unwrapped simultaneously during a tuberculosis epidemic.”

But this overt hubbub, Wheen reminds us, was only part of it. There was also the strange and less-known fact that, during the Seventies, many of our leaders were — for various reasons — slightly unhinged. Their principal mental abnormality was a tendency towards paranoia, a tendency that, Wheen demonstrates, came to dominate the period and left its legacy in conspiracism and bizarre ideologies.

There was President Nixon — the world statesman, author of détente and visitor to China — raging half-cut through a crepuscular White House, ringing underlings during the night (one night’s log recording nearly 50 calls) or holding absurd conversations with his staff about who is out to get America, who is out to get him and who he is out to get. And his words are picked up on the recording system he installed to vindicate him to posterity but which ultimately, of course, undid him. In another room of the White House, R. Gordon Liddy, a member of Nixon’s security unit, has organised a screening of Leni Riefenstahl’s Triumph of the Will for presidential staff.

In the United Kingdom, so sapping have become the almost daily verbal assaults on Harold Wilson, the Prime Minister, by his own close aide Marcia Williams that Wilson’s doctor suggests to other members of the entourage that she be secretly poisoned. They turn down the suggestion and watch their boss becoming ever more enfeebled and beset by Williams’s tantrums. Inflation rises to 20 per cent. Wilson suspects that the South African and US secret services are out to get him and believes that he is being electronically eavesdropped on by Russian trawlers while holidaying in the Isles of Scilly. Some MI5 employees believe that Wilson is a KGB agent.

In China Mao Zedong and Lin Biao are at each other’s throats. “The most populous country on Earth,” Wheen writes, “was governed by a pair of raging hypochondriacs and psychological basket cases, each plotting the other’s downfall.” Idi Amin rules Uganda, while President Nguema of Equatorial Guinea abolishes the national bank, has its former governor executed and takes personal control of the treasury.

The intelligentsia are convulsed by pessimism. Professor Peter Gunter of Texas University, writes that “30 years from now the entire world, with the exception of Western Europe, North America and Australia, will be in famine”. The oil crisis after the Yom Kippur war of 1973 fans speculation about an end to civilisation. The decade gives birth to Baader-Meinhof, the Red Brigades, the Tupamaros and other bastard children of Che. The British revolutionary Tariq Ali hails the guerrilla “execution” of the German Ambassador to Guatemala. Under Edward Heath, Wilson’s predecessor, there are five declarations of emergency in four years, after 25 years in which there had been only two. Northern Ireland turns from being a troubled province to the location of a dirty war. The top civil servant, Sir William Armstrong, has a full nervous breakdown during the industrial crisis of January 1974, and tells a meeting of permanent secretaries to prepare for Armageddon. He is admitted to a mental hospital. Sir William, Wheen writes, never returned to Downing Street. “Instead, after a decent interval, he became chairman of the Midland Bank.” Ah, those were the days.

There are predictions of coups. Wheen recalls coming to London in late 1973 and seeing that the Christmas edition of The Spectator carried an article entitled “A military coup in Britain?” Such talk was rife among Britain’s editors, senior officers, politicians and businessmen. Wheen, who arrived in the capital with a guitar and discovered that he’d missed the Sixties, was aware of the gloom. As a student communist at the same moment I was part of a fabulous delusion. In 1975 we produced a poster entitled History is on our side. It showed the fingers of a hand. They were marked Portugal, Vietnam, Mozambique, Angola and (the shame of it now) Cambodia. The idiocy was shared; the following January Lord Chalfont presented an ITV documentary in which he stood by Karl Marx’s tomb and declaimed that communism had more or less already arrived in Britain.

There is the paranoia of the loser (husbands lose out to wives because of feminism), there is generational paranoia induced by moral change (Wheen describes the famous Oz trial, in which George Melly’s slang term for cunnilingus, “yodelling in the canyon”, was a pinnacle moment). There is the paranoia caused by the accidental — 1972 remains the record year for aviation deaths.

There is the almost justified paranoia in reaction to bad state behaviour. Wheen details the process leading up to the 1976 report of the Church Committee into illegal operations in the US and abroad by the FBI and the CIA. The report found levels of surveillance that were far greater than people either had understood (there were 500,000 FBI files on individuals and groups) or would support. Worse, even, it was made clear that the agencies felt entitled to intervene to discredit perfectly legal opponents. The Watergate burglary was an offshoot of this mentality.

For all this, my favourite chapter is Wheen’s survey of the psychic absurdities of the period, and in particular his recollection of how Uri Geller was treated by the BBC and scientists alike, as the miracle man who would transform our understanding of the natural world. There is no one like Wheen for reminding people who need to be reminded of how stupid they have been. And here, however, I should declare an interest, especially since Wheen is part of the team responsible for Private Eye. When I tell you that this book is funny, mordant, unforgiving, intelligent and — I think — true (and it is all these things and more), you ought to know that he has said something similar about my recent book, Voodoo Histories. If you do buy Strange Days Indeed, though, I think you’ll find that one of us, at least, is right.

Strange Days Indeed: The Golden Age of Paranoia by Francis Wheen (Fourth Estate, £18.99; Buy this book, 383pp)

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