Alan, naturally

For the past 18 months, Alan Titchmarsh has been travelling the length and breadth of the country to paint a TV picture of the geographical, natural and human history of the British Isles. He has descended a waterfall in Yorkshire, climbed one of the highest mountains in Scotland and flown in a jet aircraft at 600mph along the coastline.

But the presence of the nation's best-loved gardener in Darlington had nothing to do with his nationwide tour filming the new BBC1 epic series British Isles: A Natural History. He was installed behind a table in Ottakar's bookstore in the centre of town to meet and greet that strange breed of person known as the Titchmarsh fan.

As the queue formed in anticipation of his arrival, the manager decided to install crowd control and cordon them off in an orderly fashion. Not that a Beatles-style frenzy of crazy fans was on the cards. Titchmarsh, once voted into second place behind George Clooney in a sexiest man on TV poll, attracts ladies of a certain age.

A succession of such women files past him, carrying bags of shopping and clutching books to be signed. He cheerfully presents a card and a cake to a store member celebrating her birthday. He signs a farewell card to be given to someone in another store. He admires the cross-stitch brought along by a woman on her way back from a Help the Aged sale.

His reason for being there is to promote his latest fictional book, Rosie, which took him two years to write. "It did take quite a while but we got there in the end. It was fun to do and I try to explore the age gap a bit," he says, talking while continuing to sign books.

The story centres on an 86-year-old dotty widow, the Rosie of the title, who decides it's time to live a little. She helps her grandson find a soulmate while opting to live life to the full and to hell with the consequences.

This is his fifth novel. Previous ones have sold well and won him awards, although I doubt if a prize presented for best bad sex scene in a book has a place on his mantelpiece.

"I have made progress as a writer," he says. "Rosie is just a different type of novel for me. Someone asked me, 'Is it different to the others?' but it just latches on to things that are boring into your brain.

"We are not the age we seem. Young people can be very old and old people can be very young. It's a bit of a cry - just because you get past 50 doesn't mean you are written off and don't want to be adventurous any more."

As Ilkley-born Titchmarsh is four years past his half-century, perhaps we should read something into this. After all, he's given up two of the programmes with which he's closely associated, Gardeners' World and Ground Force, and embarked on a new career as a natural history guide with the British Isles series. All that and moving house.

The phrase "midlife crisis" doesn't pass my lips, but he bridles at the suggestion that he's given up gardening. "I'm still doing two other gardening programmes," he points out, his genial manner turning slightly spiky. "I just didn't want to do the same programme until I dropped off the end of my perch. I haven't stopped, I've developed."

Travelling all over the British Isles making the series was "amazing". Filming took him from the Northern-most tip of Scotland to the Isles of Scilly. "It was a wonderful experience and reinforced what I already knew - that the variety of these islands, for their size, is tremendous," he says.

He's always had a fascination for natural history, belonging to the Wharfedale Naturalists' Society when he was a youngster. The gardening really grew out of that. "I've always been interested in natural history and I think if you're into things that grow, you're into things that fly, crawl and swim," he says.

He worked with a team of researchers and producers on the eight-part project. It wasn't just a case of standing in front of the camera and doing what he was told. "I say what I say. I am not just a puppet," he says in much the same tone that accompanied the "I haven't given up gardening" reposte.

There were so many "best bits" that he finds it virtually impossible to list his favourites. An encounter with red squirrels and climbing the mountain next to Ben Nevis when it was snowcapped on a summer's day do merit a mention.

"There is so much. I think people will be astonished what they can do in their own little pattern of islands," he says.

Making the series was not without incident. Filming near Hadrian's Wall, a BBC helicopter's tail rotor failed and it started spinning around, missing Titchmarsh by about 50ft, before crashing. Luckily, no-one aboard was badly hurt.

Just as well-publicised was the incident when he and the crew were filming on a beach in North Devon and were cut off by the incoming tide. Titchmarsh clambered up the cliff, called for help and then went off for a cup of tea. Even so, the rest of the crew had to wait two-and-a-half hours for the tide to retreat before being guided to safety.

"They were carrying stuff and I wasn't," he says, explaining his solo getaway.

He already has another BBC series lined up that has nothing to do with gardening - The 20th Century Roadshow, which is like The Antiques Show only more up-to-date. Titchmarsh is particularly pleased with his role as he's interested in 20th century collectables, from old motor cars to signed photos of film stars. Filming begins next month on the series that is due to be screened on BBC1 next year.

Just to prove there really is no escape from him, he's working on yet another book - a Christmas volume for publication in December 2005. This will be an anthology of stuff he's written and stuff he's used over the last 15 to 20 years to make up a Christmas entertainment book.

His schedule makes it surprising that he's ever at home to celebrate Christmas. He points out that TV work has always taken him around the country, even presenting Songs Of Praise.

He was aiming to fly back to his Hampshire home, a Georgian farmhouse, and wife of nearly 30 years Alison after the Darlington book-signing. "It's very nice to go travelling and so much nicer to come home," he says, echoing a song lyric.

* Rosie (Simon and Schuster) £16.99.

* British Isles: A Natural History begins on BBC1 on Wednesday at 8pm. The BBC book is published on October 4, at £19.99, and the DVD of the series is released on November 8.