Harry takes the monarchy back to doing its royal duty

Since we are used to seeing images of Prince Harry staggering drunkenly out of Boujis with a blonde on his arm, the pictures of the prince in military fatigues on the front line in Helmand come as something of a shock.

But while even the hardest-hearted republican must surely doff his hat to a young man risking his life for his country, the news of Harry's Afghan adventure has wider implications. For it might just be the best thing to have happened to the monarchy for 60 years.

Until yesterday, the sandy-haired young man third in line to the throne was a symbol of everything that was wrong with the royal family.

After controversies about his educational achievements - or lack of them - at Eton, he seemed to have drifted into a lifestyle of expensive cocktails and perma-tanned blondes. The nearest he came to combat was the nightly punch-up with the paparazzi.

And while his grandfather Prince Philip saw action in Crete and Sicily in World War II, Harry seemed likely to go down in history as the prince who thought it funny to wear a Nazi uniform to a party.

But whatever doubts we may have about the war in Afghanistan, which seems to be slipping ever further out of control, Harry, like his comrades on the front line, now deserves our respect.

When he comes home, the old temptations may well assert their grip. But we owe a debt to all the men and women who serve their country - and that means the pleasure-loving prince, too, especially since he could so easily have stayed at home.

Still, while Harry's tour of duty is a proud moment for him and his family, it is also a reminder of the paradox at the heart of our political affairs.

Harry's ancestors, after all, were a distinctly martial, even bloodthirsty family. For, indirectly, the Windsors sit on the British throne only through right of conquest: if William the Conqueror had not fought at Hastings, or Henry Tudor at Bosworth, then our history might look very different.

And as any schoolboy used to be able to tell you, the legitimacy of the Royal Family has always been bound up with military service.

We remember Henry V as a dashing hero-king for his victory at Agincourt, not for his bowl haircut. And as late as 1743, in the age of coffee houses and global trade, George II personally led his army into battle against the French at Dettingen, with the same happy result - a result that helped to confirm the place of the German- born Hanoverians in British hearts.

None of us expects the modern monarch to perform similar heroics; indeed, even George II's army was really run by his military-minded son, the Duke of Cumberland. Still, the connection remains vitally important to royal prestige. If the family does not command the nation's armies, then it is nothing. So the Queen - like her presidential counterparts in France or America - remains our Commanderin-Chief. And from time to time, junior royals have kept up the tradition. Victoria's grandson Prince Maurice was killed in World War I, and the Duke of Kent in World War II. And, of course, Prince Andrew served bravely in the Falklands - although he never came as close to the front line as Harry in Helmand.

But with warfare becoming increasingly professionalised, and with celebrity culture gaining ground at home, the image of the royal family has rather lost its martial lustre.

Meanwhile, like the Church of England, the other great institution through which kings once exerted their control, the Army has become progressively detached from our daily lives. Few of us go to church; even fewer of us fight for our country, and the royals are no exception.

The danger for the monarchy has always been that it would go the way of other historic institutions, sliding into self-indulgence, public contempt and ultimately irrelevance. And the answer has always been for it to stand as the embodiment of public service, of sacrifice, of individual commitment to a greater collective good.

That was what compelled George VI and his family to remain in London when the bombs were falling in the Blitz, and that was what his daughter dedicated herself to when she became our Queen more than half a century ago.

Yet, in an age of individualism, consumerism and celebrity, it is more difficult than ever for pampered princelings to keep sight of what Gordon Brown would doubtless call their "core values".

As early as the Thirties, Edward VIII lost sight of his duty and paid the price when he was compelled to abdicate. Diana seemed to rekindle the fire when she visited Aids patients in hospital, but she eventually succumbed to the lure of the paparazzi and the glossy magazines - as her younger son, until yesterday, appeared to have done, too.

Harry says he enjoys being "with just a normal bunch of guys, listening to their problems, listening to what they think". It must make a hell of a change from the usual chit-chat at Boujis.

But to hear him talk of his excitement and pride at taking on the Taleban, we are suddenly returned to an older age, when the royal family genuinely embodied the values and ambitions of the nation, and when kings and commoners found themselves side by side in the last ditch.

It is an experience that was denied both his father and his grandmother, who as youngsters led sheltered lives of impossible privilege. It is an experience that the royal family was palpably missing when the only people they regularly met were creepy lackeys like Paul Burrell.

But it is an experience that in future, more of our rulers must share - for their good, and for ours. Whoever would have predicted that it would be Harry, of all people, to show us the way?

Dominic Sandbrook's latest book is White Heat: A History of Britain in the Swinging Sixties (Little, Brown).