The last time I had spoken to Christopher Lambe, he was enjoying a raucous send-off before leaving for a tour of duty in Afghanistan. Between rounds of tequila, I asked what his expectations were for the next six months. "I expect it's going to be pretty 'punchy'. Summer tours normally are. We've been warned that the Taliban prefer to fight in the summer. This is what we've all been training for, though. This is why I joined the army, not to march around Buckingham Palace in shiny boots."

Now Captain Lambe - or "Lamby", as he is known among his fellow Welsh Guards - is lying in the military wing of Selly Oak Hospital, Birmingham, unlikely to walk for a year after being shot in the knee. Yet his first thought is for the men he has left behind. "I feel guilty. I'm in this extremely comfortable hospital, with fresh food, and being looked after by my girlfriend, and now have to watch the rest of the operation on TV, knowing someone else is doing my job and leading my men."

It's been a grim time for the Welsh Guards battle group. Five men were lost in five days, and in total 196 British personnel have now been killed in Afghanistan since 2001, with the number of casualties far higher. The military wing of Selly Oak is full of British soldiers with injuries that range from severed limbs to severe burns.

Lamby had an idea what to expect when he boarded the plane to Afghanistan with the rest of 1st Battalion Welsh Guards in April. He knew that the next six months were going to be tough, and that he was going to probably the most dangerous area of Helmand Province, south Nad Ali; but no one on that flight had any notion just how bloody Operation Herrick was going to become.

Lamby had been in Iraq 18 months before, but that had been a "frustrating tour". "Other than one small ambush, time went very slowly in Iraq. It's a reconstruction project. I felt more like an observer out there than a soldier." Shortly after arriving in Helmand, the Welsh Guards suffered their first casualty, Lieutenant Mark Evison, who died after being shot on a patrol. "When Mark died, it really sank in where we were. After the initial shock, our natural reaction was to mourn the loss. Even as a soldier, when you hear about casualties, you still feel distanced from it. But I knew Mark well. Yes, you go back to your tent that night and say a prayer, but the next day you have to get up again, get over it and get on with the job."

A few weeks later, just before midnight on 19 June, Operation Panther's Claw began. Lamby's role was second-in-command of 2 Company. On the night of 28 June, the platoon were heading to their checkpoint - a mud-walled compound - to "get their heads down for some kip" before advancing with the attack the following morning.

As the sun rose, Lamby was preparing the radios for the day's assault. There was a shout from one of the guardsmen and he looked up to find the checkpoint had been surrounded by Taliban fighters with AK-47s. “I can't remember what happened next, other than hitting the dirt floor. I knew I had been shot and I could see the brown dust I was lying in turning red. A medic dragged me into a nearby ditch to get me out of the crossfire.
It was only then that I really considered the prospect that I might not be returning home. I passed out and woke around 45 minutes later in the back of an American Black Hawk helicopter with a big American sergeant crouched over me.

“'You sure had one hell of an escape, sir. You're going to live, you're going be OK,' the sergeant grinned.

“At that point, I burst into tears. I knew I was going to get a chance to see my friends and family again. I called my mother first and told her there was good news and bad news. I was coming home early, but I had been shot."

Two days later, Lamby was back in Britain watching Wimbledon in the hospital ward. While the sense of relief has not worn off, the reality of the past few months is beginning to sink in. Two days after he arrived at Selly Oak came the news that the Welsh Guards commanding officer, Lieutenant Colonel Rupert Thorneloe and his driver, Trooper Josh Hammond, had been killed by a roadside bomb. "When I switched on the news and saw Colonel Rupert had been killed, I thought there must be a mistake, but then, no one is safe in Afghanistan now."

Only a few weeks earlier, the Welsh Guards lost another senior officer, Major Sean Birchall, a company commander. In Afghanistan, the initial shock will subside. The grief will be short because it is not part of the mindset of a soldier on operational tour, where there is no time for political rights and wrongs. From his hospital bed, Lambe reflects: "The time for remembrance and mourning is when the tour is over and you're back home. For now, the guardsmen know they have a job to do, and they'll just crack on and do it."

Henry Sands is a former officer in the 1st Battalion Irish Guards