Sometimes, reading the advertisements in this paper can have a dramatic effect on a teacher’s life. Just ask Nick Welford.

One Friday afternoon, nearly two years ago, Nick, a science teacher at Chipping Campden secondary school in Gloucestershire, was sitting in the staffroom flicking through The TES, when he came across an advertisement. “Sailing with attitude,” it said. “Wanted: tutor to sail across the world with family.”

Nick, now 29, had learned to sail as a child and was immediately interested. “I always planned to go travelling when I’d raised enough cash,” he says - teaching was partly a way of paying off his college overdraft. “My friend said, ‘you’ll never do that”. So I said, ‘right, I’m going’.”

He called the number, was put through to a woman called Claire Spencer for a phone interview (for which he was “totally unprepared”), and two days later met the rest of her family at their home in London. “We clicked immediately,” says Nick. “You know, when something just seems right?” That was in April 2000. Nick resigned from his job two days later, told his girlfriend, Louisa, he’d be away throughout her finals year - “she stopped breathing for a bit” - and the following October set sail with the Spencers on their new 51ft yacht, Attitude, from his home town of Poole, in Dorset. It was the start of a 12-month working holiday that turned out to be the journey of his life - a 16,000-mile voyage to Australia via the Canaries, the Caribbean, the Panama Canal, Tahiti, Fiji, and numerous islands, waters, beaches and breakers in between.

Claire and Jonathan Spencer first thought of sailing round the world five years ago. Both successful business executives - Claire, 41, with a PR firm, and Jonathan, 46, with a property developer - they had been together for 18 years, had two growing children and a four-bedroom home in south-west London. But they were tired of the rat race and desperate to get off the treadmill.

“I was racing just to keep up,” remembers Claire. “Nothing excited me any more, and life was increasingly weary.”

After a few years of sacrifice and saving, the Spencers had the means to realise their dream. Yet Claire was keen that their children - William, 12, and Hannah, 10, who both attended private schools - didn’t miss out on their education. Hence the advertisement in The TES. Thirty people replied, but it was Nick who fitted the bill. “There was instant chemistry between us, all of us,” says Claire. “As soon as he walked through the garden gate, I knew. He was just so easy-going.”

Nick sailed with the Spencers a few times during the summer before they left, but nothing could have prepared him for the adventures ahead. “The places we went were stunning,” he says. “The islands, places I’ll never go again, the diving, people we met, the things we saw - it was all unbelievable. And I was paid.”

The Spencers paid Nick pound;100 a week to keep William and Hannah’s education up to scratch, and he went about his job with a professional attitude. He visited their schools to talk to teachers and get copies of their syllabuses, and worked out a timetable for their lessons on board - three or four hours a day of one-to-one tuition arranged around his “watch” shifts and the cooking rota, with “school holidays” built in. They took a cupboard full of books and other resources, and used a CD-Rom encyclopaedia to look up information that Nick didn’t have to hand.

Luckily (for he also slept right next to them), Nick “got on really well” with the children, and both teacher and pupils learned a huge amount. How could they not? “It was such a long trip I think the kids enjoyed having a bit of structure to the day and keeping their minds active,” he says. “They couldn’t really be naughty because I’d just tell their parents. It helped me, too - I’ve now taught two full curriculums of all subjects.” All except Latin and French, that is, for Nick left the language teaching to Jonathan and Claire.

Claire now says that the children’s education was a concern - “particularly because they were at such a formative stage. So it was quite a challenge for Nick. But we were very happy with his teaching, and the children loved it. He was very good at integrating what was going on around us with the curriculum.”

Nick says he never felt like an employee. “And the whole experience was such an education, how could I fail? There’d be dolphins jumping over the bow of the boat, so we’d just go and watch them. I’d point out the blow holes and talk about them. We spent a lot of time talking.”

They also spent a lot of time swimming and diving, not to mention fishing, snorkelling, windsurfing - Nick tried to windsurf across the Panama Canal (a failed attempt to show off, he says) - and “fixing things”. He says:“I learned that I’m good at not taking things too seriously. There were a lot of problems with the boat at first, but I found I was good at fixing them - getting the water pump working, mending the freezer, or whatever. We were good at dealing with things together.”

He didn’t miss much either, apart from Louisa, of course, his three nephews, his mum’s chutney, and “keeping warm under the duvet on a cold night”. Even the weather was “fantastic” most of the time, “although, once I was trying to teach physics and a wave splashed over the deck. I was like, ‘OK, I think we’ll put the books away’.”

Despite living “cheek by jowl”, tension with the family was “remarkably non-existent”, he says. Even his “hideous” seasickness didn’t upset things too much.

“He handled it so well,” says Claire. “And you knew when he was better because he started singing Tom Jones songs again.”

One week, Nick had to look after the whole family while three of them were laid up in a Tahiti hotel with dengue fever, a viral disease that causes acute joint pains, and Hannah was in hospital having pins removed from a broken arm. “He played mother to all four of us,” says Claire.

Nick’s easy relationship with the Spencers was put to its greatest test when he was stung by a Portuguese man-of-war while snorkelling near the Marquesas islands. “I was stung all over my back and neck and under my arms. I’ve never had so much pain,” he says. “The air was blue. I was trying to apologise to Jonathan because the kids were there, but I didn’t know what to do. I was beside myself.”

After failed attempts to soothe his sores with vinegar and bicarbonate of soda, Claire called the doctor who had treated Hannah’s broken arm. “He said urine’s the best thing,” remembers Nick. “I was half-laughing but really I was beyond caring.” Putting normal niceties aside, the Spencers (apart from William, who refused to pee on his teacher) filled a large saucepan and poured it over him. It worked.

Louisa joined the boat for the last leg of the trip, and they sailed into Gladstone, Australia, last August. The family later headed back to London to pick up their lives while Nick and Louisa “overlanded” it to Cairns on Australia’s north-east coast. They’re still there, Nick working as a supply teacher and looking after Attitude while they plan a trip to New Zealand next month.

And after that? “It’s all a bit up in the air,” says Nick. “I’m not in any rush to get back to teach in England. And I think I’m pretty much done with sailing, for now.”

But not with adventure, it seems, for he and Louisa are hoping to travel back home through Africa in her father’s Land-Rover. “But there have been many, many plans,” says Nick, as easy-going as ever. “We’ll have to wait and see.”

You can read more about the Spencers’ year at sea on their website: www.spencersatsea.com