Nineties TV heart-throb Robson Green has made quite the splash in the fishing world. He tells Gabrielle Fagan about feeling like a teenager, his hopes for his sons and why being around nature feels like therapy

As the rejected suitor of a fisherman, I’m not disposed to warm to Robson Green.

The Geordie actor, whose 30-year career has included TV hits like Soldier Soldier and Wire In The Blood, and most recently, a highly successful role as gruff cop Inspector Keating in Grantchester.

He has also become a superhero for anglers. Millions are hooked on his fishing series, which began in 2008 with Extreme Fishing With Robson Green. Since then, he’s matured into one of the world’s most experienced fishermen, and is currently demonstrating his skills in his new series, Robson Green’s Ultimate Catch.

And it’s not just those with a keen interest in tackle talk that he’s caught the attention of, by injecting sex-appeal into the UK’s most popular participatory sport.

Stripped to the waist to reveal his hairy chest, he flexes his muscles and wrestles scaly, flapping monsters out of rivers and seas and into his arms, and then professes his sincere admiration for them by exclaiming, “Look at the size of that!”

He’s far more lyrical out of the water than in it – his fishing catchwords are of the pithy variety; “we’re in”, or “get in” – but on dry land, he enthuses: “Fishing’s such a beautiful activity which makes perfect sense to me. It’s like a therapy, because you are surrounded by nature, and that helps you get a proper rhythm for life.”

As he gazes at me with his piercing blue eyes and talks, about turning 50 and finding himself, I can distinctly feel the Robson Green charm reeling me in.

That milestone birthday (he turned 50 on December 18) was hugely at odds with how he feels inside. “I remember being young, and looking at someone who was 50 and thinking, ‘Why are they bothering to live?’, because it seemed so old and boring,” he says with a chuckle.

“Luckily inside, I feel like an 18-year-old, with the spirit inside me as adventurous and young as it ever was. I still have wide-eyed wonder about the amazing things I’ve seen, in an extraordinary life travelling all over the world for my career.”

He’s relieved that, instead of seeing career opportunities dwindle as he’s aged, they’ve actually increased.

Over the last 12 months, as well as Grantchester, he’s made a second series of Tales From Northumberland, a documentary about his beloved childhood home, where still lives.

Undeniably the most physically demanding commitments were filming Ultimate Catch and reprising his role in action-packed Sky 1 series Strike Back, based on the novels of former SAS man, Chris Ryan.

Green, a muscular 5ft 9, doesn’t, however, take his fitness lightheartedly, and has a regimented routine of five gym sessions a week, eats healthily and never drinks alcohol.

“It’s essential I look after myself, because of what I put my body through in stunts as an actor, and even more through the fishing journeys,” he says. “Trekking through jungles is tough. We don’t escape to hotels and if I’m living with tribes on the bank of a river, I camp out under a canopy or kip in a canoe.

“In this new series, I go further than ever in pursuit of a fish I’ve always wanted to catch – the Golden Dorado, which lives in the middle of nowhere in Bolivia. We had to trek for days to find this ultimate fish, avoiding caiman crocodiles hungry for their next meal. One swam past my legs, and thanks to him, I discovered I could still run pretty fast!”

He’s faced his share of personal turbulence on dry land, too. He’s been married twice, and in 2011, his 12-year marriage to former model, Vanya Seager, ended. The couple have a 14-year-old son, Taylor.

“Relationships sometimes don’t work, and that’s life,” Green says philosophically. “That’s what happened with me and Vanya, but we’re on good terms and she’s an astonishing, beautiful woman and a wonderful mother. Our wonderful son Taylor is very bright and sporty and is doing incredible things, so it’s all good.

“My advice to him as he grows up is to find something that truly makes him happy, and then he’ll never have to work again,” he adds. “That’s how it is for me – I pursued two things which really fulfil me, fishing and acting, and it’s led to so many great things, and I’ve got paid for it. It’s never felt like work.”

His current girlfriend, “an account manager for a big clothing brand”, shares his love of the outdoors.

“We both like the countryside and walking and she finds fishing peaceful.

“Marriage? I have no time – there’s too much fishing to be done!”

Over the last decade – particularly since the death of his father in 2009, a miner also called Robson – he believes he’s found himself, and matured.

“Although I’ve never gone off the rails, when I was young I was reckless, and it was all about Robson. But I’ve learnt so much from experiencing different cultures, meeting different people, as well as having the time to observe nature and the behaviour of wildlife in my travels.

“Nowadays, I know who I am, have a sense of identity and self-worth, and know where I’m going,” he says.

“I realise that contentment comes when life is about others; family, friends, and giving and investing in people and experiences – all far more valuable than material things. I can’t wait for more adventures.”

Robson Green’s Ultimate Catch continues on Quest on Fridays