These days, they carry Amtex, not AK27s. They don’t wear khaki, they prefer crinolene, but Operation Rolling Thunder is still a major pull.

War is still a big draw 40 years after the recapture of Saigon and the end of the Vietnam War.

So, once you have done all the elderly pagodas and experienced all the wonderful and delicious things Vietnamese cooks can create with what, on the surface and if you look long enough at, looks like some rice, the inside of a golf ball, some bamboo shoots, soya sauce and a fish resembling John Hurt, everyone heads for the tunnels at Cu Chi.

This is the Ben Dinh site near Hoi Chi Minh city.

During the war, 20,000 people lived there in a three-level underground network that stretched more than 200 kilometres.

Only two foot wide by three feet high and housing factories, hospitals and entire villages, the Cu Chi tunnels have been extensively modernised and modified.

They now cater for mass tourism, which means widened to accommodate massive amounts of massive tourists with massive rear ends.

Once only tiny PLAF (People’s Liberation Armed Forces) fighters in khaki could use the tunnels.

Now they can be accessed by a Teletubby with a camcorder.

I got caught in a bottleneck behind three post-menopausal American ladies with ambiguously coloured lacquered hair. All were from California and claustrophobic.

The narrow corridors were the homes of the ‘human moles’ who frustrated General Westmoreland, the 25th Infantry and the 242nd Chemical Detachment. It’s where the Tet Offensive was planned.

The Vietcong called them Region 1V. The South Vietnamese called them the 111 Corps Tactical Zone. The Marines called them ‘The Iron Triangle’. The holiday brochures and the hotel foyer flyers call them a ‘must-see’.

These tunnels are where they sheltered from Agent Orange and the brutal Operations Crimp (1966) and Cedar Falls (1967).

These are the famous holes that gave the ‘Tunnel Rats’ their name. The Australians called themselves ‘Tunnel Ferrets’.

Spliffed up, they volunteered to flush out the revolutionary heroes from their subterranean bolt-hole. Few came back and, if they did, not in one piece, mentally or physically.

Deadly snakes, scorpions and killer bee hives awaited them along with coconut mines and needle-sharp bamboo punji canes.

The tiny tunnels now cater for mass tourism, which means widened to accommodate massive tourists

They were a maze. Nowadays they are signposted. Once you have seen the tunnels you can have your photo taken with your arm around a mannequin independence fighter or in front of a ‘downed’ US chopper.

There’s also a gift shop selling cans of hot Heineken, gory photos, books with gory photos, spent cartridges, authentically bashed-in helmets and bullets with realistically buckled noses.

You can buy some fetching repro guerilla fatigue-wear. US dollars and Vietnamese dong are both welcomed. Once someone gets hold of your dong they won’t let go.

An infamous battlefield has become an enormously popular amusement park.

On simple school classroom chairs in a timber frame hut in a small patch of regenerated jungle, you watch a video presentation depicting , if the electricity supply holds out long enough, the long but ultimately victorious struggle against the evil, raping, bubble-gum-chewing imperialistic forces.

You are then marched along dirt tracks through the undergrowth as your guide points out bomb craters with a stick.

Nobody in Vietnam can let anyone forget the war. The atrocities have become an asset.

Once, all those years ago, someone would tear your head off if you came anywhere near the entrance to the tunnels. Now, they merely tear off the corner of your 25,000 Vietnamese Dong entrance ticket.

The killing fields now have rest rooms and a picnic area.

But the biggest pull is the buck-a-round Markmanship Stadium. It’s a rifle range. And you have your choice of four ‘Geek’/ V-C (Victor-Charlie) targets.

I watched as one tourist, a Brit, pushed up his Raybans and settled them on top of his wavy hair. He was handed a gun, weighed it for a moment. He shook his head: “Give me a M60. M16’s are no good.”

He was handed another gun. He weighed it approvingly then let it rest on top of a brick pile. He screwed up his eyes and looked down the barrel.

He took a few calming breaths then squeezed the trigger and shot off a tenner's worth in the blink of an eye.

He was from Manchester and it was the first time he had shot a ‘Charlie’. The man who gave out the shells clapped him on the back: “Good shooting, buddy.”

The tourist’s prize was a polyester gook hat. You can get them anywhere. They are good for fishing. A jet screamed overhead.

“Medic! Medic!” someone shouted out.

“We have a sick man over here!”

There were giggles. Behind them a group of schoolchildren smiled. Their teacher didn’t.