At the Caen Memorial Museum, a large crowd of journalists were taking their places in the lecture theatre. Accompanied by a phalanx of minders and asistants, two men were hurried into the hall and ushered on to the stage. From all the fuss, I imagined that the men were French government ministers about to announce astonishing new details of the huge programme of events being held for the 50th anniversary of D-Day.

But no: they were the heads of the French television channels 2 and 3. They had come all the way from Paris with nothing more sensational to reveal than the extent of this summer's coverage of D-Day events on French TV: '50 years of D-Day celebrations - 50 hours of television.'

The details of this announcement were enthusiastically reported in the next day's papers along with the mass of other D-Day stories that nowadays bulk out Normandy's daily newspapers.

Normandy is deep in the throes of D-Day delirium. To provide a taster of this mild insanity, sample two of the events previewed in the press last week: a D-Day Golf Tournament and a D-Day Way of Liberty Cycle Race. By the time we get to June I shall not be surprised to see that plans have been laid for a Mr Blobby D-Day Fun Run or a D-Day Jubilee Bungee Jump from the top of Pegasus Bridge.

Philippe Gay, director of the Calvados Tourist Board, says that strenuous efforts are being made to 'preserve the meaning' of D-Day. 'The Sixth of June is a day for the veterans: 40,000 are expected to attend the celebrations. It will be a day for their memories, a day to allow them to come together again.'

When historical celebrations fall into the hands of regional tourist departments, however, experience tells us to prepare for events that are geared rather more towards popular entertainment than any sort of dignified ceremonial or cultural enrichment.

With Normandy expecting to attract double its usual four million visitors this year, the region is looking forward to a substantial boost to its economy as a result of the celebrations. The Normans can therefore be forgiven for trying to cash in on the event.

The Mayor of Caen has meanwhile tied himself in knots trying to find ways to include the Germans in the D- Day anniversary celebrations. 'Where would the German dignitaries stand during the re-enactment of the landings?' one of the organisers demanded. 'In the bunkers,' came the practical reply.

There is nothing glib either in the Caen Memorial Museum. It is a stunning exhibition: much more than the usual collection of faded newspaper clippings and rusting military hardware. With thoughtfully presented displays, the museum sets out to explain how the world stumbled into war in 1939. And, impressively, it deals unflinchingly with such subjects as collaboration with the Germans, deportation of French Jews, and the role of the Vichy government - all of which the French are presumably happier to forget.

And here, in the memorial, you are reminded that D-Day was an endeavour of breathtaking courage. The well-detailed atrocities of the Germans invite you to contemplate what could have happened if the invasion had failed - which, as the exhibition makes clear, it could easily have done.

The memorial is the place to come if you want to see D-Day as the great historical drama it was, sketched out in every important detail.

As you drive around the D- Day places of Normandy, it becomes clear that there are two D-Days. There is the poignant event in history, and the tourist extravaganza with its cycle races and golf tournaments.

While no visitor to the sites would want to ignore 'historical' D-Day, my heart cannot help warming to 'tourist' D- Day. I spent most of my childhood fighting the Germans. The playground chant 'We won the war/in Nineteen Forty-Four' was the prelude to a rousing Britain-versus-the-Nazis encounter.

The Second World War obsessed us all. We avidly read about war in comics with characters such as Rockfist Rogan and Captain Hurricane. There were endless war programmes on television. Most of all there were the war films. We all thrilled to The Great Escape, but the film that made the biggest impact on our back-garden battles was The Longest Day, the story of 6 June 1944.

We particularly liked John Wayne who, having broken his leg in the airborne landing near Ste Mere Eglise, instructed the medic simply to replace his boot. 'Lace it up - tight]' he drawled before limping off, probably with the intention of heading towards Berlin to capture the Reichstag single-handed.

And then there was Robert Mitchum, pinned down on Omaha Beach warning his cowering troops: 'By nightfall there's gonna be just two sorts of people left on this beach. Those who are dead and those who are gonna die.' And, I remember thinking at the time, there would also be those like me pretending to be dead in the hope of getting out in one piece.

It is now impossible for me - and probably for a whole generation - to look at the D-Day beaches without seeing shadows of Wayne, Mitchum, Fonda, et al.

Before setting off to Normandy, my 12-year-old son and I sat down in front of The Longest Day, all two hours and 50 minutes of it. This is about the only war film he has ever seen - for goodness sake, the poor lad has never even had a toy machine-gun to call his own. He was enthralled, watching the fighting on the beaches with particular horror. 'I wouldn't have fancied getting sand in my boots,' he mused.

We started our tour, where The Longest Day effectively begins, at Pegasus Bridge, about five minutes' drive from the Brittany Ferries terminal at Ouistreham. Except that for the moment there is no Pegasus Bridge: what the Germans failed to blow up, the local council pulled down last November. A new bridge should be in place by June but it will not be the same.

We visited Madame Arlette Gondree-Pritchett, the owner of the nearby Pegasus Bridge cafe. She took us down to the cellar and showed us where she sheltered with her family that night behind a cider barrel. It was here, she pointed, that she sat on the lap of an army captain who gave her her first taste of chocolate. The events of that remarkable night suddenly came alive for us.

Brittany Ferries has produced a pack of tapes which provide a tour of the three beaches in the British sector from Ouistreham to Port en Bessin, finishing at the Battle of Normandy Museum in Bayeux. The tapes partly explain the events of 6 June, but they are mostly personal recollections of the participants (including some Germans).

Anxious to save time, I was keen to fast-forward through the tape, which meant that we quickly lost our place and earned me a stiff telling off from my son. Guided by the tape, however, we enjoyed the German Bunker Museum at Ouistreham and were stirred by the sight of the Mulberry Harbour at Arromanches. But, while almost every town along the coast here has a museum of some sort, unless you have an insatiable appetite for the subject, few are worth stopping for.

Listening to the taped recollections of men who had fought on 6 June - and listening in the very places where these events had taken place - was intensely moving. The Bayeux Battle of Normandy museum is worth a quick look. However we both preferred to linger at the Bayeux Tapestry, now handsomely accommodated in an intelligently arranged museum in the centre of town.

Any D-Day tour should include a stop at one of the well-kept war cemeteries: a reminder of the human cost of 6 June. Since reading the poetry of Keith Douglas ('Remember me when I am dead/and simplify me when I'm dead'), I have long wanted to visit his grave in Normandy.

Douglas, aged 24, commanded a tank when the Sherwood Rangers landed in Normandy on 6 June. He was with the first Allied regiment to enter Bayeux the following day. On 9 June, his regiment was stuck in the difficult country beyond Bayeux near Tilly-sur-Seulles. After completing a hazardous investigation of the enemy's positions, Douglas had returned to his tank squadron to make his report, when they came under mortar attack. His biography reports: 'He must have been hit by a tiny fragment, or by the blast, for although no mark was found on his body, he was instantly killed.'

His grave is to be found in the war cemetery at Tilly-sur-Seulles in plot 1, row E, grave no 2. I looked in the visitors' book to see if anybody had come back to remember him - but nobody had.

We completed our tour of D-Day sites by driving up to the American cemetery at Omaha Beach. The huge expanse of row upon row of more than 9,000 simple white Carrara marble crosses is an affecting sight.

The place that both my son and I most wanted to see, however, was Ste Mere Eglise. The scene from The Longest Day that remained most firmly lodged in our minds showed the airborne soldier whose parachute becomes lodged on the church tower leaving him hanging there helpless, looking down with horror at the slaughter of his colleagues in the square below.

Here in Ste Mere Eglise, the uncomfortable triangle of historical event, commemoration and commercial tourist exploitation is neatly completed. For visitors like me, who come here led by The Longest Day, there is a surprising sight: hanging permanently from the church roof by a parachute is a dummy paratrooper. Bad taste? Perhaps. Good for tourist business? You bet.

Welcome to the D-Day trail . . .

(Photographs omitted)