It’s never too late to change your mindset and better yourself,” Ant Middleton tells me.

Which might sound trite coming from anyone else, or cliched at best. But hailing from this mighty man, who could add a cape to his signature black clothing, join the superheroes or at least clench a cutlass between his teeth when being interviewed, it’s good advice.

Throw in his achievement of achieving the elite forces holy trinity serving in the Paras, Marines and SBS, an ability to dodge bullets, kill the enemy, fight in wars and probably escape from a desert island using a bandana and a toothpick, I was all ears.

Besides, his tough love/self help/macho message, which has proved such a huge success both on and off our screens, helped turn his life around when he threw in the towel with the army and landed himself in jail.

Picking himself up, dusting himself off and sorting himself out, meant that he can now boast some hugely successful TV shows to his name; SAS (Who Dares Wins), Mutiny and Escape.

Which explains why he is touring his Evening With style show, enlightening us about his daring exploits while offering some inspiration and advice.

“I wanted to engage with people, particularly the younger generation and encourage them. As a role model it’s important that I inspire people. I just want people to believe in themselves and have a more positive mindset, because believe me – I have been there.”

And he certainly has. Born in Portsmouth, his life began to unravel when his beloved father died of a heart attack aged just 36. Replaced by a “bully” of a stepfather,Ant signed up for 9 Para, the airborne division of the Royal Engineers, as soon as physically able, aged 16.

He served in Afghanistan but became disillusioned, quit the Army and joined the Met police before being kicked out after being caught drink-driving.

Constantly in fights and moving back to Essex, he then met his wife Emilie, and with her encouragement joined the Royal Marines and later became a sniper in the Special Boat Service.

After leaving in 2011 he hit another low point, assaulted two police officers and spent four months in prison. He calls the incident “a turning point in my life”.

It was then that Ant Middleton changed his viewpoint and launched his highly successful adventure/ reality TV career based on his experiences and motivational message.

He really has got a story to tell then. He smiles and shrugs: “You have to get out there and try it, learn through your mistakes. Fight your own battles. I didn’t have anyone to look up to who was there for me and it got me down and into trouble. But you can’t live like that.

“You have to take responsibility for your own actions. We live in such a massive blame and snowflake culture but you have to hold yourself accountable and find a solution.

“You have to flip it 180’ into a positive mindset, so I try to see everything in a positive way and it works for me.

“It gave me a new lease of life and made me a better person. But I still say what I want and of course I offend some people.

“Not everyone will be happy with what you want to say. And that’s OK too.”

That he is also a properly nice guy, who takes life with a pinch of salt and is as happy at home with his wife and four children, as he is adrift on the Indian Ocean with a bunch of miscreants, only enhances his attraction.

I liked him a lot. He is a man’s man for sure, but he’s not arrogant. Yes he could climb K2 naked or swim the Amazon without goggles on, but he’s also surprisingly down-to-earth.

This is his second theatre tour, back by popular demand, the last having sold out. But does Ant actually like standing up on stage? Could this man, who’s as happy in the desert in full combat gear as the bath, be equally at ease in front of an audience?

“No!” he chuckles, “I was completely out of my comfort zone to start with, and kept wondering what on earth I was doing. But by then everyone was so involved that I couldn’t back out of it.

“I knew I had a good story to tell and they had come there to listen to me which helped. So I went out on stage and admitted I was slightly nervous. I told a few jokes to show I wasn’t too serious because people think I’m the same in real life as I am on TV. You just have to get the audience on side.”

And now, two tours in, has it got easier? “I can do it in my sleep.” Of course he can. “But I like learning new things and bettering myself, taking myself out of my comfort zone so I took it on as a challenge.”

So when does he relax, if ever? “Work and family have always come hand-in-hand but I just want to be the best father I can be. You can’t change the past but I know I have changed as a person.”

As for the future, Ch4 is screening a documentary of his attempt to climb Everest in the next few months, as he became caught up in extreme weather conditions near the summit. And the next series of SAS (Who Dares Wins) is being filmed soon.

So after all this time has the novelty worn off? “No. I still find it very exciting. This is a privileged position and a massive responsibility. I love it.”

And the mantra of Ant Middleton’s life so far? “Be true and honest. It’s all you can hope for.”

  • See Ant Middleton at the New Theatre Oxford, on Monday. For tickets call 0844 871 3020 or go to atgtickets.com/oxford