It was the moment Alan Titchmarsh - Britain's favourite gardener, best known for his calm and unflappable manner - admits he felt "very frightened".

"I hoped I wasn't going to die, and I was hanging on in there but the pain was so acute at one point I thought it might be a blessed relief," he says.

The TV presenter who's enjoyed enduring popularity over decades, appearing on shows from Gardeners' World and Ground Force to the Chelsea Flower Show, is talking frankly for the first time about the dramatic day last April when he had to be airlifted to hospital and underwent surgery.

With a family history of heart disease - his father died suddenly in 1986 from a heart attack at the age of 62 - there was obvious concern for the 67-year-old when he started suffering pains in his chest.

"The pain lasted and was absolute agony and every bit as agonising as a heart attack," he recalls.

"At first I thought it was indigestion as I know that can give you chest pains - but it didn't wear off. I didn't know what was wrong and although I didn't think it was a heart attack, because the pain wasn't going down my arm (a common symptom), it was frightening.

"Actually I think it frightened my wife more, because of my family history, of course. The men in my family have a tendency to die from heart disease at a relatively young age."

After his wife, Alison, called the emergency services, Titchmarsh was taken to the nearest hospital to his Isle of Wight home, St Mary's and then airlifted to Portsmouth's Queen Alexandra Hospital, where he was diagnosed with gallstones and had surgery to remove his gall bladder.

He now takes statins on the advice of his doctor to help lower cholesterol and, thankfully, after the straight forward operation, has had no more trouble.

Yorkshire-born Titchmarsh is now focusing on his latest novel, Mr Gandy's Grand Tour.

The book's hero isn't dissimilar to the author - a middle-aged man who enjoys painting, travelling and boats, and finds himself a magnet for attractive women.

Inspiration for his plot, he says, came from a desire to explore the scenario of a man who'd remained in a long, unsatisfying marriage, but on becoming a widower, suddenly takes off on an adventure on his own.

"My wife always reads my books first and when she read this one she asked me, 'It's not about us, is it?' I said, 'No, of course not.' After all, P.D. James never murdered anyone, but she wrote brilliant crime mysteries. I just wanted to show men can be as sensitive as women and tell a good tale," he says with a smile.

Although he's been urged by his family to "take life easier," he confesses it's difficult because, "I don't want to retire as I think you need a sense of purpose and a reason to get up in the morning. So I'll always be a gardener, I couldn't do without that - it's part of me. I love the writing which is solitary and then I have a balance of the fun and socialising of the TV work. So far, it's a perfect mix."

He enjoys Royal approval - recently the Queen gave him keys to the back garden at Buckingham Palace for a documentary, and he's toured Highgrove Royal Gardens with Prince Charles, who describes Titchmarsh as a "friend".

While he acknowledges he still finds it "scary and rather shocking" that he's lived longer than his father ("You automatically assume your father will be senior to you forever") he's happy that he was able to witness his success.

"He loved seeing me get on and that's a big comfort. I'm very content and still happy to cope with the unpredictability of not knowing what's around the next corner. I still feel like someone in their mid-40s," he says.

"I'm often accused of being relentlessly cheerful, and in company, I am because why would you burden other folk with your problems? Anyway, I've got no reason to be grumpy, and if I occasionally am, I'll give myself a talking to. I've been incredibly lucky and never expected the life I have."

Mr Gandy's Grand Tour by Alan Titchmarsh is published by Hodder & Stoughton, priced £18.99.