In my life as a film director, I have been unofficial travel agent and tour guide to some of the world’s most demanding actors. I escorted Scarlett Johansson through Italy while filming A Good Woman, and Reese Witherspoon across the hinterlands of California for Best Laid Plans. I’ve learnt to deal with erratic behaviour, outlandish demands and overzealous paparazzi chasing down my actors. So, how difficult could it really be to take my two children – Ella, 8, and Cas, 6 – on holiday in southern Vietnam?

We are wandering the street markets of Ho Chi Minh City when crisis strikes. Two rival stallholders have designs on my offspring, eyeing them as commercial prey. Suddenly, Cas is grabbed by both women at once and pulled back and forth, tug-of-war style, until eventually one triumphs and my son is bundled away around the back of her stall.

I try to cry out in protest – but I’m being grabbed by another trader, who wants to sell me a shirt. I’m a big man, I know, but the “replica” Ralph Lauren number she says is my size looks more like a tent. I break free to find my son shaken but smiling – dressed in a fake Arsenal football kit. “Ten dollars, very cheap.” That’s when I notice that Ella has gone.

My annoyance quickly turns to aggression. Then panic. The narrow corridors between the stalls are crammed with a swirling mass of people, and seem impossible to search. Both kids have identity tags on them, but the sense of shock and the single-minded determination to make everything right again strike me bodily. With Cas clutched firmly by the wrist, I charge from stall to stall, pushing behind, in front and underneath. The heat suddenly hits me, the 99% humidity, the horror. How stupid am I?

“Dad.” There is Ella, beside a smiling saleswoman, holding up a synthetic-looking pink dress. “What do you think?”

The children were the centre of attention almost everywhere we went – but scares like that were rare. They were stroked and pinched, prodded and poked, but always with a smile. Ella would wave like a movie star, soaking up the spotlight. For Cas, it was sometimes too much. He would take refuge, hiding his head against my belly until he was given the all clear.

Mostly, the approaches were welcome – like when we needed to cross a road, for example. The thousands of scooters that swarm through the streets of Ho Chi Minh City, with utter disregard for traffic lights, police or each other, are extraordinary to behold. Which is just as well, because we must have stood on the kerb for at least two hours waiting to cross. Finally, a very old woman offered help. I was reluctant, because she was so doubled over that her entire world-view must have extended no farther than her handmade shoes. Too late – she was pulling Ella towards certain death, and, as a responsible parent, I had no choice but to suspend my survival instinct and follow. Somehow, like smoke in a wind tunnel, the moving mass of motorised people flowed around and not into us.

In his holiday journal, my son has stuck a ticket for the Ho Chi Minh Museum. Underneath is written “This was rubbish”, and stuck below that is another museum ticket, with “. . . but this was worse.” And after dragging the children around the city’s temples, museums and French colonial architecture, I was inclined to agree with him. For all of us, the real fascination of Ho Chi Minh City was the way people live on the streets, their small shops doubling as living rooms at night.

Lit only by the red glow of the shrines that adorn every house, they huddle around low tables to eat their family dinner on the pavement. The Vietnamese kids would circle my two, who were looking all bashful and puppy-like. Then a few giggles and a shove, and, before you knew it, they were pen pals for ever.

More worrying, for me at least, was Ella’s journal. It will have to be destroyed. Under the heading “Best thing we did on holiday”, it reads: “Massage.” She has then pasted in a whole collection of pictures of women in traditional dress. The title? “Some of dad’s masseuses.”

We travelled out from Ho Chi Minh City along the Mekong delta, where small white children are rare beings. As we passed among the floating markets, boat after boat came to our side – their occupants not anxious to trade, but to pinch the kids’ cheeks and say hello.

The Mekong was my favourite leg of our tour. The thousands of tiny channels that crisscross the delta define the south Vietnamese way of life, offering not just a glimpse of a world past, but a peek into the future. Fish farmers are replacing the fishermen, their farms moored the length of the river; and every so often we saw a mansion perched absurdly among wooden shacks – a nugget of new prosperity, its gilt gates and crystal chandeliers ostentatiously lighting up the wealth for the neighbours to see.

We had arranged a home-stay in Phong Dien, which meant walking a couple of miles along the river, the kids slowed by their rucksacks. I was anxious to make good progress in order to miss the worst of the rising mosquitoes as the sun set. When I turned to look behind me, there were 30 or so people following the kids, stroking them, offering to carry their bags, laughing and smiling. A five-year-old boy led Cas into a shack on the side of the river. Inside were two chairs, a small table, a polished concrete floor and, in pride of place, the largest and most violent video-arcade game I have ever seen.

They played, or rather murdered, each other over and over for a couple of hours, no words exchanged, as I sat watching the sunset reflect across the surface of the dark-brown river, the mosquitoes chewing their way up my leg.

It was at our home-stay that I got my biggest fright of the trip. We had eaten a feast of freshly caught elephant-ear fish; I had had a cold beer, the children a rare Pepsi. I was letting them burn off the sugar before we climbed into what the Vietnamese called a bed – in English, it would be a wooden platform.

Both kids were climbing trees in the back garden, laughing. I was reflecting on how wonderful it was to be with them, and to stay with our Vietnamese hosts. That’s when I heard the first scream – it was coming from the house and was very persistent. Investigating, I discovered the familial grandmother peering out over the window ledge, ashen-faced. A second later, her son shoved me aside and ran at the children.

It was only later that I understood how close a call it had been. Vipers sleep in trees at night: the snake’s poison could have killed Cas or Ella in 30 minutes without treatment. The nearest antidote was 40 minutes away.

Our final stop was Da Lat, an old colonial hill station up in the mountains. We drove through dramatic landscapes where men and water buffalo have carved a living from the rough terrain. It is a place painted in primary colours: the image of the red soil set against deep-green jungle will stay with me for a long time. The only dent in that memory is the soundtrack: the beeping of Game Boys from the back of the car.

Da Lat is a romantic town – the French once called it Petit Paris. Lined with large 1930s villas, including a remarkable summer palace built for the emperor Bao Dai, it even claims its own Eiffel Tower – except that this one is a small radio mast painted red and white. The kids claimed I had lured them there under false pretences.

They did love our digs, though – at the Crazy House, an architectural flight of fancy built to resemble a giant monster mask, with melting turrets, statuesque women carved into the walls and a giant giraffe poking up above the tearoom below. Think Gaudi – but even CAMBODIA We were lodged in the Eagle Room, a suite of interconnected caves with some sprawling mattresses and a tiny Alice in Wonderland table and chairs. In the centre of the chamber was a giant egg, and above it a huge eagle with wings outstretched. The egg was an open fireplace. The kids were absolutely thrilled to be there, and I read them chapter after chapter of Harry Potter until they finally fell asleep. That’s when I realised the fire was spewing smoke – and showed no sign of letting up. I had to stay awake all night with all the windows open.

We made it to morning without choking to death, and that proved to be the last of our Vietnamese perils. On balance, I had preferred travelling with Ella and Cas to travelling with Hollywood actors. Yes, I was outnumbered by my children, but that often proved a boon. If there was a dull-looking museum, I would always put it to a vote: shall we, shan’t we?

That’s the beauty of kids – they are so gloriously predictable. They swam; I tried another cocktail.

Travel details: Explore (0870 333 4001, www.explore.co.uk) has a 15-day Voyage through Indochina – part of its family programme – that includes Ho Chi Minh City, a boat trip along the Mekong delta, Da Lat and Angkor, in Cambodia.

Prices start at £1,799 for an adult and £1,499 for a child (aged 5-11), including flights from Heathrow to Vietnam and return from Cambodia, 11 nights in hotels and one in a longhouse, local flights and all ground transport.

Other operators include The Adventure Company (01420 541007, www.adventurecompany. co.uk) and Responsible Travel (01273 600030, www.responsibletravel.com).

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