AFTER a five-minute monologue about his latest TV adventure, Griff Rhys Jones draws a breath and offers an apologetic grin.

"I've been round in a huge circle and included everything," he says with a short chuckle. "Sorry."

And it's true, he has gone on a giant rambling circle about his series - Griff's Great Britain - touching on everything from the regional differences in naming parts of British scenery, the ignorance he and his late comedy partner Mel Smith had about UK geography during their early career ("We didn't even know Leeds and Bradford were quite close together!"), to the "extraordinary" eagle's nest, full of "rotting carcasses", he saw near Loch Lomond.

Long as his speech is, it is rather pleasant to listen to, punctuated with exasperated sighs, snorts of laughter and the odd twirl of his glasses while he mulls over his latest journey around our local shores.

After 40 years in the business, it's this ceaseless enthusiasm and talkative style that has become Jones' stock in trade.

Whether it's his late father's time as a medical officer in Burma during the Second World War, immersing himself in Dylan Thomas' dying days to work as the executive producer on BBC drama A Poet In New York, anger management, or even his comedy partnership with Smith, his passions are worn firmly on his sleeve and discussed at length.

Born in Cardiff in 1953, Jones, who lived in Wales for six months before his father's job as a doctor took the family off around the UK, eventually settling in Essex, has been a mainstay behind and in front of TV cameras since the late Seventies.

After studying at Cambridge University, he worked as a radio trainee and then teamed up with Smith for their long-running series Alas Smith & Jones, later amassing a fortune by selling Talkback, the independent TV production company they'd set up.

Over the past decade, Jones' career has taken an unexpected turn, with the comedian becoming the go-to man for effusing about the beauty and diversity of our isles.

There has been BBC's Rivers With Griff Rhys Jones, Mountain, the Three Men In A Boat series, as well as last year's A Great Welsh Adventure for ITV.

Next up, he will explore eight disparate kinds of British terrain, taking on challenges like weaselling, which is "squeezing though tiny gaps in granite tors - a bit like rock climbing, only through holes", exhibiting a giant vegetable at a show and catching sheep.

Intrepid and outdoorsy as this sounds, the 62-year-old is not, he's at pains to point out, the next Bear Grylls.

"My wife was watching the weaselling stuff and she said, 'This is good. You do it so much more entertaining than Bear Grylls'. And I said, 'Why?', and she said, 'Because you're groaning and moaning the whole way.'"

Although he goes for a run every day, Jones, who has been married to graphic designer Jo for more than 30 years and has two grown-up children, admits that some of the physical challenges are more gruelling than they were in his youth.

"I'm fitter now, certainly, than I was at 30 - a lot, lot fitter and that's just a choice, a lifestyle choice that I made," he says.

"I did the Fastnet Race this year, that's a six-day ocean race. I wanted to film that but no one would film it, but I sail with 20 year olds.

"What you notice is in the old days, I could get myself up a mast and do what I needed to do and I can still do that, but it just hurts more. So you can't jump off things; some of the bounce goes."

Comfortable in front of the camera, Jones admits he sometimes misses the spotlight when he's on holiday, because it means forgoing "the amazing support" that comes with filming a series.

"When I went to the Galapagos Islands, I found we were all in a queue," he admits with a laugh.

"You arrive in parties and you see the other parties going around, who have just walked past all the birds to get back in the boat. When I was walking around, I kept thinking, 'I'd rather be making a TV programme for this - I wouldn't have all these people with me for it!'

"And then the boat I was in caught fire. It burst into flames, there were 50ft flames on it. In the middle of the night, I had to jump off and swim to another boat and all the time I was thinking, 'I'm doing this and there are no cameras?'"

Recently, Lenny Henry and Danny Baker, also no slackers when it comes to reeling off funny anecdotes, have been the subject of semi-autobiographical dramatisations of their lives. Would Jones, with his collection of humorous tales, like to follow suit?

"Well yes, it's [his memoirs, Semi Detached] certainly for sale if anyone wants to buy!" he teases. "Nobody's made me an offer."

But with another TV production company - Modern - and new adventures to steep himself in, there's little chance of Jones sitting around twiddling his thumbs in the meantime.

"The truth is that I use television shamelessly to pursue my own personal delight," he explains. "I sort of feel at my age, that there are lots of things I haven't done that I ought to try, in case I find it really exciting and worthwhile doing - and surprisingly, many of these things turn out to be hugely enjoyable.

"It's a bit like I feel that time is running out," Jones adds, "and you need to go away and try all these things before it's too late."

*Griff's Great Britain begins on ITV on Monday, January 4