Alan Clark, the scandalous Tory diarist, was a member of the Bullingdon at Oxford, the boozy dining club that later included David Cameron and Boris Johnson among its members. Mind you, Clark was there a few decades before them, when Bullingdonians were made of sterner stuff. On one occasion, according to Ion Trewin’s biography of the late Tory minister, the Bullingdon boys turned up on horseback with real swords and proceeded to cut up the waiters and each other.

Eton-educated Clark was ideal Bullingdon material: arrogant, flamboyant, rich, right-wing, thoughtless, vain, brutal and jolly good fun. Others add a few more epithets. According to Dominic Lawson, former editor of The Sunday Telegraph, the late trade minister was “sleazy, vindictive, greedy, callous and cruel”. He was also an unashamed admirer of Adolf Hitler, kept a signed photograph of him in his study, called his dogs after Hitler’s female followers and delighted in showing his collection of Nazi memorabilia to guests at Saltwood Castle.

Mind you, even members of Human Rights Watch collect Nazi relics. And you can’t blame a man for being attracted to women, even three at a time in the case of the Harkess “coven”. Well, actually, you can, and Trewin’s authorised biography, while fascinating, is just a little too indulgent. The trouble with Clark is that everyone wants to make excuses for him. He was the lovable rogue, the great English cad, with his cars, gambling, wine and women. The reality was rather different.

Clark was a hypochondriac all his life, often incapacitated with depression – the kind of psychological weakness that he scorned in others. He was a military historian and army enthusiast who flunked national service and exaggerated his own military record. His notorious philandering, recounted in exotic detail in his Diaries, was predatory and often brutal. When he first met his wife Jane, at the age of 14, he recorded in his diary that she was “the perfect victim”. Clark pursued anything in a skirt, his long-suffering secretaries in particular, and was not above procuring illegal abortions for his girlfriends, despite being outspokenly pro-life.

As a minister he was unreliable, lazy, duplicitous and vain. Margaret Thatcher tolerated him because of his relentless sycophancy towards “the Lady”, which evaporated as soon as she lost power.

Clark should never have been allowed anywhere near the Board of Trade, let alone the Ministry of Defence, where he was a junior minister responsible, appropriately, for procurement. It is inconceivable that anyone like Clark could become a minister today, even in the Conservative Party. Yet it is only 10 years since he was being feted by his party, and the media, as a straight-talking, politically incorrect man of the people. A kind of ministerial Jeremy Clarkson.

I came across Clark when covering the Iraqi supergun affair in Westminster in 1991. British firms had provided the barrel for Saddam’s giant gun, capable of firing nuclear-tipped shells 600 miles, in defiance of an arms embargo. The whole thing was pure John Le Carre, with spooks, arms dealers and the murder of the weapons expert, Gerald Bull, who designed the gun. It later emerged during the Matrix Churchill trial that ministers, including Clark, had been, in his words, “economical with the actualite” about their willingness to license the export of arms-making equipment to Saddam Hussein. Clark came clean in court, but he had been prepared to see innocent men go to jail and was unrepentant about arming Saddam.

I wasn’t close to Clark socially – as a hack I was only a couple of notches above a waiter in the social pecking order. But he was a great lover of Scotland, and had an estate in Eribol which he visited whenever he could. Clark’s Scottish roots were deeper than most people realised, and his middle name is MacKenzie. His family money came from a cotton thread manufacturers in Paisley – the firm that became Coast Patons – something he didn’t boast about because it would have sounded nouveau riche in the grand circles he moved in after he acquired Saltwood Castle in Kent.

Clark was great fun, indiscreet but you couldn’t help liking him, just a little, even while being repulsed by his right-wing views. He was overtly racist, and considered standing as a candidate for the National Front. He said all immigrants should be sent back to “bongo bongo land”. He treated women’s issues with contempt – to the extent of being drunk at the dispatch box delivering a speech about equal pay. We should never forget that Clark was a monster. John Le Carre, who knew him in the 1960s, tells Trewin that Clark was “very, very close to fascism... he actually had a potential for evil which was very unusual”. Alan Clark’s last political campaign was his defence of the Serbian leader, Slobodan Milosevic. It takes one to know one.