"Has anyone here ever been shot at?" God, is it already 21 years since that thawing Cold War afternoon of drizzle and cloud on Salisbury Plain? Standing around with a few dozen fellow platoon commanders on a training course, I was waiting to be reminded just how to identify an enemy firing position when the instructor sparked a moment of sudden interest with his question. Yet despite many of us there having already served for two years or more, only one man raised his hand in response. His experience had involved a few bullets, a few seconds of shock and an unseen gunman in South Armagh.

That short event, though, had him marked out as remarkable among us. The army that I had joined was still training for a conventional conflict in Europe. Northern Ireland, by then a theatre where the prospect of getting shot at was anyway fading by the month, was very much a secondary priority.

So until 2001, aside from a few veterans of the anomalous 1982 Falklands War, those involved with the five-day charge through surrendering Iraqis in 1991 and a small number of special forces troops, a whole generation of British army officers, from top to bottom, remained unblooded, their true leadership abilities untested.

I don't remember much else of that lesson. A few years later, I know that I recalled thinking, shot-at-a-lot while reporting in Bosnia, that the instructor had concentrated too much on explaining the "crack" and "thump" acoustics of bullets, and never once mentioned the "zip" and "zing" that they make when they are truly close. But then probably he had never been shot at either.

However, during many assignments in Helmand province over the past couple of years I have often thought about that afternoon. It isn't merely the naivety of a past era of untried leadership that contrasts with the experience of British commanders in Afghanistan now. "War" as we knew it does not exist any more. "Getting shot at" is quite unremarkable (and anyway preferable to "being IED'd" - that is, blown up by a road-side device). And killing and dying have very new implications.