It’s early morning and Craig Murray — our former man in Uzbekistan — is making himself a cup of tea in a Blackburn semi during his doomed attempt to unseat the foreign secretary Jack Straw in May’s general election. His towel slips and he is exposed, our nudest ambassador.

“Oops!” says Murray, “losing my dignity. Not to mention my towel. Careful where you’re putting that camera. Children might be watching. Old ladies might faint with shock. Young ladies might faint with lust.”

They might, but that seems unlikely. Murray is 46, and has the body of a devil sick of sin. But he does have a 25-year-old Uzbeki girlfriend and a liking for a drink and talks openly about the joys of sex. So, you might say, no wonder Jack Straw’s men fired him.

Being a sexual pervert, a crook or a drunk has never been an impediment to a fine career in the Foreign Office: Donald Maclean once defecated on the carpet during a party thrown by an American diplomat and it was all hushed up. Nothing untoward happened to the traitor until he upped sticks and defected to Moscow.

Today, one senior figure at King Charles Street is said to be a serial shagger — “everybody knows about it” — having allegedly bedded at least two female Labour MPs, and nobody has cut down his ration of Ferrero Rochers.

Although Murray admits he is a bit of a lad, he insists that he is not a drunk or a crook or a perv, and remains deeply wounded that the Foreign Office accused him of selling visas for sex, of being off his head on booze and stealing Her Majesty’s dosh: “They hit me with 18 charges and I was cleared on all 18.” His crime, he says, was to commit the sin of sins, to criticise the way America was running its war on terror, in private and in public.

He challenged the credibility of Uzbeki intelligence given to the Americans and British, saying that it was based on torture. X and Y and Z were confessing to be major players in Al-Qaeda, said the raw material from the Uzbeks. Rubbish, said Murray, pointing out that in President Islam Karimov’s neo-Stalinist central Asian despotism, they boil people alive, and worse.

In a series of telegrams to Straw, copied to MI6, the lawyers and all the senior players, Murray argued that a) intelligence based on torture was useless because a torture victim will confess to anything, and b) that it was morally wrong — “we are selling our souls for dross”.

Straw saw the telegrams, says Murray, and came to the judgment that Her Majesty’s government should continue relying on the boil-in-the-bag intelligence.

This issue wasn’t academic for the ambassador. Within days of starting his job in Tashkent in 2002, photographs of a corpse landed on his desk. He sent them off to Britain, to be analysed by a Home Office pathologist.

The victim was a supporter of Hizb ut-Tahrir, a fundamentalist Islamic organisation but one that professes non-violence. Murray says: “The main finding was that this person had died from immersion in boiling liquid. And it was immersion, rather than splashing, because there was a clear tide-line around the upper torso and upper limbs and complete burns coverage underneath.

“Obviously the idea of someone being boiled to death is pretty horrific and that was one of the first eye-openers that I found in Uzbekistan.”

Most British ambassadors would have huffed and puffed in private, and said nothing in public. Imagine the fuss, then, when Murray spoke his mind in a speech in Tashkent in October 2002. Lines such as “Uzbekistan is not a functioning democracy”, “brutality is inherent” and just the mention of the secret police “boiling men to death” went down like a lead balloon. The uproar in central Asia was heard in Washington DC.