I joined the Royal Marines when I was 16 – I'd grown up wanting to be a soldier, to be part of an elite force. I'd served two tours of duty in Iraq before I was sent to Afghanistan, where the sense of ever-present danger – of actually being at war – was far more intense.

While there, I was involved in some of the fiercest fighting. But the one point when I thought, "This is it, I'm about to die", when there was no doubt in my mind, came in the early hours of 9 February 2008.

It was dark and I was silently searching a compound we suspected was being used by the Taliban to make bombs. I sensed a slight tension against my shin, the kind of feeling you'd get walking into a bramble bush. But there was no shrubbery around us, only grass and dirt. At the same time there was a pinging noise, familiar to anyone who's ever pulled the pin from a grenade.

I had walked into a tripwire. Looking down, I saw the primed grenade at my feet. I shouted to the rest of my group, "Grenade! Take cover!" but there was barely time for the others to react. I suppose it was partly a sense of responsibility that made me act the way I did. Since I had set the thing off, it felt as if it was up to me to rectify the situation. Tearing my day sack off one shoulder, I jammed it against the grenade and then lay beside it in the foetal position, to create a barrier between it and the other guys.

It felt like being five years old and riding your bike into your dad's brand new car, leaving a dent – that gut-wrenching feeling as you wait for the consequences. I knew I had perhaps four or five seconds until detonation, and I counted them down in my head. I'd reached seven or eight, and was about to relax, when it went off.

As the plumes of orange sparks and the smoke cleared, I knew, at least, that I was still alive. But the blast had deposited me, face down, several feet away and there was still the awful possibility that I might reach down and find a leg missing.

When lads receive a traumatic injury, they don't always realise. I've seen people trying to get up and simply falling over, because they've lost one or both their legs.

The patrol medic ran over and gave me a head-to-toe check. I was disoriented, and there was a lot of blood coming out of my nose and ears, but he told me that I seemed fine, apart from a few cuts and bruises. My eardrums had been perforated, but there was no lasting damage. My backpack and body armour had absorbed most of the impact of the explosion, and my helmet was peppered with grenade fragments. The backpack had been torn clean off my back and lay in tatters 10 metres away. None of the others had suffered anything more serious than minor shrapnel wounds.

The lads took me to see our commanding officer and told him what I'd done. He was incredibly relieved and asked me how I was feeling. I felt a little fragile and had a terrible headache, but that was it.

People react to extreme situations in many different ways, and I've never been one to dwell or retreat into myself, nor do I suffer from post-traumatic shakes, as some do. My inclination is simply to move on and get on with the job, so that's what I did – we spent the next couple of hours quizzing men from neighbouring compounds and returning the fire of a nearby sniper. Afterwards, a check-up in the hospital at Camp Bastion confirmed that I'd sustained no lasting damage.

I was rather shocked when I learned I was going to receive the George Cross for conspicuous courage – apparently the first one to be awarded to a marine since the second world war. I've undoubtedly had my own life saved by other lads' quick thinking, and on that particular day it was simply my turn. That's just how you get through each day. I don't give my award a second look now. It's a replica, of course – the real medal's valued at £200,000, so it's kept at the Imperial War Museum.

You might say I've used up my nine lives, but it doesn't really work that way. I know people who have been killed or badly injured just two weeks out of training, while others can last for months in conflict zones without so much as a scratch. It's something I try not to dwell on too much – I can't afford to; I'd do it all again if I was asked to.



• As told to Chris Broughton

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