The tortured expression of fighting-fit Adam Whiteoak is set to persuade hundreds of youngsters to sign up for the Royal Marines.

The teenager's face has been used in an advertising campaign to try to encourage others that if they have the mental and physical stamina there is a role for them in the famous commando team.

But the advert pulls no punches.

In it Adam, of Sutton-in-Craven, is shown in agony as he undergoes the Marines' tough exercise regime. And this was no stunted up picture.

His father Stuart said the picture was not posed but taken on an actual training exercise. The fitting slogan on the poster bearing Adam's face is: 'You've never known so much pain. Want to know more? 99.99 per cent need not apply.'

Famously, Prince Edward was one of those who couldn't take the pace and decided for a less physically-demanding life on civvy street.

But Adam went all the way. During his bid to be able to wear the green beret, the former South Craven School student had to prove his skill with firearms, undertake survival exercises on Dartmoor, take part in amphibious training and carry out a 30-mile cross-country march.

But he was one of only six out of 56 recruits to get through the gruelling seven month training course at the Commando Training Centre in Devon. Stuart said: "He has proved a lot of people wrong."

His son has now been posted to Arbroath in Scotland and on 24-hour standby to fight anywhere in the world.