I’ve been in a bit of a state of shock recently — and it’s to do with David Cameron. Not because I think he might make a great party leader or even prime minister — that remains to be seen. Nor even because, at 39, he’s pretty young to have got where he is. Tony Blair was only a couple of years older when he became leader of the opposition and William Hague was just 36.

It’s to do with the fact that he’s my contemporary — and the first of my generation to really make it in public life. Not only that, but I went to Oxford at around the same time as him. I know people who know him, and his friends Ed Vaizey, Steve Hilton and Michael Gove. George Osborne was at school with one of my closest friends.

So is this sense of weirdness due to the feeling that six degrees of separation — the theory that anyone on the planet can be connected with any other person on the planet through a chain of five acquaintances — appears to have gone down to just two in this case?

Or is it because I am experiencing that watershed moment that everyone must get at some point in their lives — when they realise they are getting old? The idea can form at the back of your mind when you find you can no longer read a miniature A to Z or realise you are sighing out loud whenever you sit down. But it comes crashing into your consciousness when someone of your generation scales the heights of the Establishment — and could even become prime minister.

Actually, it’s neither. The reason I’m finding this all so unsettling is that, like me, Cameron and his friends are part of Generation X — the slackers, loafers and idlers, who had been finding it hard to grow up and take life seriously. Perhaps that’s finally starting to change.

I wrote about Generation X for this newspaper in 1992. It was the deeply individualistic, nihilistic group born in the mid to late 1960s whose lives were delineated by the Canadian author Douglas Coupland in his book of the same title.

The twentysomethings I interviewed had so many choices they couldn’t decide what to do, so they generally did nothing. They were defined by their sense of alienation and the pervasive belief that things could only get worse. They were cynical, overeducated and middle class, and they competed only in “onedownmanship”.

Unlike previous countercultures, such as the hippies in the 1960s and 1970s, the only thing that united them was their loathing of yuppie culture and their refusal to climb onto the corporate ladder.

Most Generation X-ers didn’t have jobs, and those who did worked in low-paid, low-prestige “McJobs” in bars or fast-food restaurants. The really driven ones — Cameron and his friends being a case in point — went into the media as a way of expressing their individuality and creativity.

Generation X brought us the Summer of Love in 1988. Until then nightclubs had tended to be fairly unprofitable institutions, frequented by rich, usually older men and somewhat younger women, who drank champagne and danced around their handbags.

But then acid house descended from Ibiza. Suddenly clubs were full of people wearing identical long-sleeved T-shirts with smiley faces on them. It didn’t matter whether you were a busman or a lord — everyone danced the same way, drank bottled water and many imbibed enormous quantities of drugs.

It was a great leveller, a true cultural melting pot, and probably did more to erode Britain’s class system than any redistributive policies of past Labour governments, or the right to buy council houses introduced by Margaret Thatcher.

Even for those who might never have actually set foot in one of these clubs, the egalitarian, escapist sentiment rubbed off. It could go some way towards explaining the apparent contradiction of an Eton and Oxford-educated Tory leader who feels comfortable in black T-shirts and trainers and whose wife has a tattoo.