LIKE doctors and undertakers, the armed forces have their own very special brand of black humour, which perhaps helps them to deal with some of their more hellish experiences.

One serious scenario jested about by soldiers is the one where a man shouts "Grenade!" to which a colleague replies: "Don't worry, I'll fall on it!"

Such extreme sacrifice seems almost ludicrous, but heroes occasionally come along who are indeed prepared to lay down their lives to spare others, a selfless response to danger that appears to spring from them without thought.

Lance Corporal Matthew Croucher had a few seconds to react in an extreme situation. He was involved in a night raid in Afghanistan, when he felt his leg pulling a trip wire, followed by the thud of a grenade onto the ground.

The crude choice was to roll away and hope he might only lose a limb, or throw himself on top of it, making the ultimate sacrifice to save three colleagues.

He unhesitatingly risked death, lying on top of the grenade, backpack downwards to contain the blast as much as possible.

Having miraculously survived the explosion, which threw him up into the air but left him with only minor injuries including a nosebleed, L/Cpl Croucher recalls thinking: "I've set this bloody thing off and I'm going to do whatever it takes to protect the others."

The 24-year-old's backpack, stuffed with items like a lithium battery and medical kit, was more or less shredded by the blast and his body armour and helmet were dented by shrapnel.

But within hours he was reportedly back on patrol in Helmand Province, Afghanistan.

The Royal Marines Commando reservist, who's from the West Midlands, has now been awarded the George Cross, the military's highest gallantry award. He is the first reservist to receive the honour in the current conflicts in Afghanistan and Iraq.

Reading the account of L/Cpl Croucher's courage, presence of mind and selflessness, you can only sit back in slack-jawed astonishment and awe. Once that sensation has subsided slightly, you're left wondering if you would do the same in the circumstances.

And then comes the question of whether this particular marine is naturally made of far finer stuff than the rest of us, or was his response due to training and conditioning for his job?

Did Royal Marine recruiters spot something about him that said he would potentially make the ultimate sacrifice if called upon, or is that sort of special courage too difficult to identify?

One very modest former Yorkshire soldier, who prefers not to be named, but received the Military Cross for bravery in the face of the enemy during operations in Iraq in 2003, said Lance Corporal Croucher's action would have been down to a mixture of natural instinct and training.

"I don't think you could ever pick out the potential for such immense bravery in recruitment or training, but all marines are highly trained and committed to selflessness, team spirit and loyalty. These kind of core values are bred into each recruit. I suspect his instinctive response in the highly-charged situation had a lot to do with
a sense of camaraderie and loyalty."

While military personnel spend a great deal of time discussing possible scenarios and responses to them, no commanding officer would ever expect a member of the team to respond by throwing himself on top of an explosive device, says Lieutenant Colonel Woody Page, director of Royal Marines, based at Fleet HQ in Portsmouth.

"We're talking about the kind of sacrifice so serious as to be almost laughable, but L/Cpl Croucher's response was not a drilled reaction."

There are currently 6,200 regular Royal Marines engaged in action in Afghanistan and Iraq, and around 1,000 reservists also involved in those theatres of war. All of these commandos are trained to exemplify the qualities of courage, cheerfulness in adversity, unselfishness and determination.

During the recruitment process all are tested physically and mentally, and as the current advertisements for the Royal Marines suggests, the right candidates are chosen because they possess a certain "state of mind" which can be enhanced by rigorous training.

In Lt Cl Page's opinion, Lance Corporal Croucher's brave deed had a lot to do with both character and "a large dose of instinct".

He adds: "It must have been a mixture... He had four to six seconds to do something after the wire had pulled the pin from the grenade and that's very little time to think.

"He then did something that no-one would ever expect another human being to do.

"We all like to think we would do something selfless like that, but he actually did it.

"We're very lucky to have attracted that calibre of person to the Marines. He did it instinctively, and whether training helped him we don't know, but thank God he did it."

Very little is certain in life, except perhaps that Lance Corporal Matthew Croucher need never buy his own pint again, and he will always be wanted on someone's team.

"He's the sort of bloke I'd want on mine, no doubt about it," says Lt Col Page.