A few months ago, I told the editor of the Guardian that I wanted to stop writing my column for a while. "So," he said, "you're having a mid-life crisis." Unable to think of a better explanation for this desire to abandon a source of regular income, I accepted his diagnosis.
Freed from the tyranny of deadlines, I hoped to travel the world, write a book or two, mess about in boats, play more cricket. The last ambition was scuppered by the onset of a frozen shoulder; that apart, however, I've enjoyed my mid-life crisis enormously.
My first jaunt was to Colombia, whither I had been summoned by the British Council to deliver a speech about my biography of Karl Marx. During the past year or two, I've given similar addresses at pubs in Manchester, bookshops in New York, lecture halls in Stockholm and Helsinki, so it seemed an easy enough gig: talk for 45 minutes, then invite comments from the floor.
The first question bowled at me from the audience at the Bogota Book Fair was an irresistible long-hop: "Don't you think that the saddest day of the 20th century was when the Berlin Wall came down? Would not Marx have wept at the sight?" It's always a pleasure to despatch old tankies to the boundary with a walloping straight drive, and I duly did so. Then someone else piped up: "Do you not agree that Nikita Khrushchev was the most evil person of the 20th century?" This threw me off-balance for a moment. There are plenty of candidates for the title of supreme villain - Hitler, Stalin, Pol Pot, Andrew Lloyd Webber - but why Khrushchev? "Because," the man replied, "he tried to discredit Comrade Stalin's great achievements."
Once again, I hit him for six. But there were no cheers from the crowd. And then it dawned on me, rather belatedly: I wasn't dealing with a few harmless nutters in an Islington pub now; I was in a country where unreconstructed Stalinists - and Maoists, for that matter - are backed by heavily armed groups of guerrillas, who have ways of dealing with people who annoy them. About 3,700 people were kidnapped in Colombia last year: that's ten every day. It is also the country with the highest murder rate in the world.
Later that night, one of the event's organisers was rung on his mobile phone by an unidentified man who said that he and "other members of my group" were not entirely happy with my comments. Could he please tell them where I was staying, so they could come round for a chat?
Fortunately, they never found me. Otherwise I might have ended up like the Scot-tish oil-worker Alistair Taylor, who was recently freed after spending almost two years in the Colombian jungle with nothing to read except Sir Alex Ferguson's auto-biography. It makes Tony Last's fate in A Handful of Dust seem almost enviable: at least he had the collected works of Dickens.
Soon after returning from Bogota, I was packing my bags again, this time for an eight-day whistle-stop tour of Russia - from Moscow to Murmansk, St Petersburg to Siberia - in the company of Prince Michael of Kent and a small posse of Fleet Street hacks. As a socialist and a republican, I have an embarrassing confession to make about the prince: I liked him. He is serious and thoughtful, but also remarkably unpompous. (Can you think of any other member of the House of Windsor who would undertake such a trip without so much as a valet or manservant to pack and unpack his suitcases?) Russians like him, too, not least because he has taken the trouble to learn their language and study their history. He also puts in many hours of work for several admirable Russian charities.
Although he is routinely vilified in Britain, over there he seems to enjoy genuine respect and affection - whether from Kremlin grandees or old babushkas in a remote Siberian outpost. British news-papers often ask suspiciously why Prince Michael spends so much time visiting Russia. But who wouldn't, in his position?
I, too, may have to spend more time abroad if Iain Duncan Smith, my lookalike and soundalike, wins the Tory leadership. Hitherto, awareness of our resemblance has been confined to Westminster. Now it has gone national. Diary paragraphs chortling over the confusion appear almost daily; Lauren Booth mocks me in the New Statesman; even the Guardian - perhaps to punish me for prolonging the mid-life crisis - has run several letters asking if "IDS" and I have ever been seen in the same room. (Yes, actually. Soon after his election to parliament in 1992, I was advised by a friend that I really must seek out this new MP - bright chap, going places, one to watch, etc. I duly invited him to lunch in the hope of learning something useful about the Conservative Party, but as soon as we met I guessed what was afoot. That afternoon, my friend rang, unable to conceal his sniggers: "Good lunch? And, er, did you notice anything?")
What was once a joke has become a nightmare. Strangers accost me in newsagents to ask for my autograph, while cab drivers deliver helpful lectures on what the Conservatives must do under my command. Queuing at the Tesco supermarket in Great Dunmow recently, I overheard a sotto voce conversation between two teenagers. "Don't look now," one whispered, "but that's Iain Duncan Smith in front of us."
There's only one way out. I have now bought several sachets of Wella hair-dye, which promises "instant colour" in a fetching shade of blonde. I'm going to wash that man right out of my hair.