Mark ‘Billy’ Billingham is as tough as they come. Chief instructor on  Channel 4’s  SAS: Who Dares Wins, paratrooper, decorated SAS leader and a bodyguard to Hollywood superstars, he has seen extreme combat and gruelling missions aplenty. But it could all have been very different, he says.

‘I grew up in Walsall in a very poor family. I was the middle child of five. Mum and dad were very loving but there was a lot of trouble where I grew up. I was gravitating towards the wrong people; gang people. I was getting into a lot of trouble with the police. I’ve done good things and bad things, and things I’m not proud of.

‘Even as a nine-year-old, I knew what I was doing. Mum made excuses about me getting in with the wrong gang, but I was the wrong gang. I realised at that age that the people who were suffering were mum and dad.’

Leaving school early, Billy joined up. If he hadn’t, he says, ‘I’d probably be dead. Once I got stabbed in the back in a fight. In the late 70s and early 80s that was the road I was going down. Then I found the cadets. If you stepped out of line you’d get a slap on the back of the legs. I know I needed that, it kept me from gang warfare.’

When he joined up, Billy found he had total respect for his instructor from day one. ‘It was knowing I’d made the right choice. I could make it work. When you work hard for something, it feels good. Seventy started the course and only seven of us finished.’

Billy joined the Parachute Regiment in 1983 and served until 1991, holding a number of positions, including Patrol Commander for operational tours in many worldwide locations and also served as a training instructor for the Regiment as a military specialist.

After passing selection, Billy joined the SAS in 1991 as a Mountain Troop specialist, responsible for planning and executing strategic operations and training at the highest level in numerous locations including Iraq, Afghanistan, South America and Africa. He has also led countless hostage rescues.

Earlier this year, the Tories toyed with the idea of bringing back National Service, something which ended in 1960. Billy thinks it could have worked.

‘Everyone’s got their opinions and views, but I think it would have been a great idea. Fighting was a very small part of it, you could have a great career in the military that sets you up for outside. They have the best communications systems in the world, great medics, vets, engineers, medics – such a wide range of skills. Any kid leaving school who did not have a legitimate job or education could go in for two years. It would teach discipline and life skills, they’d have something to get up for in the morning. They would learn who they really are.

'I always get a weird feeling about saying I'm in the SAS''I always get a weird feeling about saying I'm in the SAS' (Image: Chris Bailey)

‘They could learn engineering, how to build roads instead of getting involved in crime. And parents would know where their kids are for two years.

‘There are so many great benefits from having National Service and afterwards they could become full-time military or step out as a better person.

‘The biggest thing that is missing from the UK is community. When I grew up everywhere had a corner shop, everyone knew their neighbours’ names. I know I definitely made the right choice. I made it work. If you work hard for something, it feels great.’

After more than two decades, Billy was in civvy street and took any job he could, making the most of the skills he had learned. He was a bodyguard to celebrities such as Angelina Jolie, Brad Pitt, Sir Michael Caine, Tom Cruise and Russell Crowe.

‘I found cameras pointing at me more unnerving than someone pointing a gun. It took a lot of getting used to as I normally kept a low profile. Ninety per cent of the job was waiting on a film set, but I did get to do some extra work. I was with Sean Penn in The Gunman. I wasn’t interested in the acting side of it, I did it for fun.’

What he also wasn’t interested in was SAS: Who Dares Wins.

‘I turned it down, I didn’t want to do it,’ he says. ‘I didn’t like the title. It’s not about the SAS, it’s about putting people through a physical, mental and emotional experience and they come out better. I approached it with trepidation and I worked very hard to get where I am now.’

Billy is sharing his experiences with a live theatre audience on a stage tour called Always A Little Further. He sees this as a chance to give something back. ‘It took a while, stepping on stage, but it never felt uncomfortable. Now I enjoy it. The only thing is that I always get a weird feeling about saying I’m in the SAS. Giving the nature of it, it’s a weird thing to admit. But now you can Google everybody.’

His stage tour gives him the chance to show his American wife, Jules, around his home country – the couple have homes in Hereford and Florida. 

Always A Little Further is at Queen’s Theatre, Barnstaple (November 6), Exeter Corn Exchange (November 7), markbillybillingham.com