Never mind Harry joining the Army and going off to fight in Iraq, what about James? Funny, not once in my wildest dreams has the possibility of my having anything in common with Prince Charles ever cropped up. Now it has: we both have sons who have chosen the Army as a career.

Mine, thank heavens, isn't quite at the Iraq stage yet, having only just had his preliminary interview, received a stack of application forms to fill in and been given a date for his RCB. From now on I suppose we're going to have to get used to speaking in initials. RCB stands for Regular Commissions Board, a three-day event, I understand, after which he will be given a number. Four means get lost, three means get lost but more politely, two is always followed by another number like 18 or 12 or six which means come back in 18 or 12 or six months when you are fitter, sharper (braver?) and have another shot. The number that all raw recruits hope they are going to get is one, which stands for Well done lad, you're just the sort of chap we're looking for, come right on in.

Until now, I freely confess, I haven't given the prospect of my son becoming a soldier and promising to fight and/or die for Queen and country much thought. There were so many other things he said he was going to be - a professional footballer, a spy, a mountaineer, a deep sea diver, an ancient historian, a millionaire, a military dictator.

It may have been his school careers department that suggested going to university with an army sponsorship. The upside of the arrangement would have been that the Army picked up the tab for both tuition and maintenance. No monthly handouts from parents, no paying off student loans for years like his elder siblings. His father thought it a great idea.

The downside would have been having to sign upafter he'd graduated for five (or was it 10?) years. I don't remember because in the end, having had a pleasant enough interview with someone called Colonel Peacock in an office behind the Horse Guards, by the time he went up to university he wasn't sure the Army was such a great idea.

So what has changed his mind? Well, a few things like the realisation that a degree in ancient history doesn't actually qualify you to do much except perhaps unpack a few tea chests containing treasures of the ancient Persian civilisation. The summer he graduated, they had just arrived at the British Museum for the forthcoming exhibition. He did write to the BM volunteering his services as an unpacker but they didn't reply for three months when the treasures were on their way back to Tehran.

He went for interviews, of course, and was offered various jobs in PR and marketing and human resources and conference management, which seems to be where all arts graduates who don't want to be television presenters end up. In between he got casual work in bars, on building sites and for something called events organisation, which basically meant laying tables in a tent for 500 people who had each paid £150 to hear Bob Geldof or John Humphrys or David Cameron talk to them after dinner.

And then at a family christening last year James ran into a friend of a friend, who, it turned out, was a captain in the Royal Engineers, or was it the Fusiliers, the Green Jackets, the Horse Guards? No, that was Colonel Peacock. My knowledge of military regiments, I'm afraid, is limited to Flashman and Bernard Cornwell novels. Anyway, it doesn't matter, Captain Corelli, as I had better call him, had just come back from six months in Iraq where his regiment had been in charge of a prisoner of war camp in Umqasr. He'd had a great time, he said. They spent all day playing football with the prisoners, some of whom, he reckoned, could have given Arsenal or Spurs players a run for their money. He was now attached to the Ministry of Defence working on some secret project, living in married officers' quarters (his wife had just had a baby) off the Portobello Road and feeling altogether pretty content with life.

How big a role Captain Corelli played in James' reappraisal of his career options I'm not sure, but the upshot was that he applied for another army interview, not Colonel Peacock this time; a fairly fierce female officer. If he gets in he plans to start his Sandhurst training next year, preferably in January. That was Captain Corelli's advice, by the way; January rather than September. That way, by the time you get to the serious outdoor training six months into the course - you know, night marches over the Welsh mountains carrying 200kg backpacks and swimming across lakes with one arm tied behind your back, it will be summer. It makes a big difference.

Someone has to do the boring jobs, they say, and, by the same token, the dangerous ones too. If I were 22, crazy about sport and fed up with living in London I'd probably choose going to Afghanistan over writing press releases for Volvo or working in a bank. And as qualifications go, a degree in ancient history is maybe no bad thing for a military dictator.