By Caroline Wyatt
BBC defence correspondent
The BBC has been given rare access to the military hospital at Selly Oak, Birmingham, and followed two gravely-injured servicemen from the Afghanistan frontline to treatment in the UK.
When we visit, the military-managed ward at Selly Oak hospital is spotless and humming with calm activity.
Almost every bed is occupied, several with soldiers who have suffered multiple amputations as well as severe burns or facial injuries. Some lie bandaged and motionless, while others chat or listen to the radio.
The hospital is currently looking after 31 military patients, including three servicewomen, most of them badly wounded in Helmand - the majority as the result of the Taliban's deadliest weapon, the improvised explosive device or IED.
Surge in casualties
Keith Porter, professor of clinical traumatology, says more nurses and surgeons had to be drafted in over the summer, both here and at Camp Bastion Field Hospital in Helmand, to deal with the sheer number of casualties.
The recent military upsurge in activity in Afghanistan doubled the number of patients at Selly Oak over the past three months.
"We are seeing patients survive now who didn't have a chance to survive only a few years ago. There have been 44 'unexpected survivors' since 2006," he says - one of the reasons the ward has been so busy.
"Military patients are very well-motivated to recovery, and sometimes you actually have to keep a rein on their progress."
He says the hospital has treated five triple amputation patients in recent months. "They were all keen to get to rehabilitation and to move forward."
That rise in servicemen and women surviving multiple injuries is the result of improved care and lessons learned from increasing experience with battlefield injuries, from the military medics who treat the wounded on the frontline, to the medical teams and pilots who risk their own lives to evacuate the wounded, and the staff who give emergency care in Afghanistan.
Once at Selly Oak, many patients will have numerous trips to the operating theatre, sometimes between 10 to 15, often for complex reconstruction work and skin or tissue grafts from one part of the body to another.
Medical lessons are being learned for use in the wider NHS from some of the experiences in the early and later stages of treating wounds.
Figures released by the MOD show the total of those wounded in action in Afghanistan rose sharply after the start of Operation Panther's Claw in June, with 46 such casualties that month, 94 in July and 59 in August.
This June alone, 44 injured service personnel were treated as in-patients at Selly Oak, and 15 as out-patients.
Brigadier Chris Parker, commandant of the Royal Centre for Defence Medicine, is proud of the level of care and welfare support now available for military patients and their families, but admits that in the years since Selly Oak first began taking military casualties, that progress has taken work from both the Armed Forces and the NHS.
"I'd like to pay tribute to the NHS staff here, because they have been very, very willing to learn and adapt.
"Some of them have even gone to Iraq and Afghanistan to work in the hospitals there, and have come back with a very immediate understanding of the needs of military patients. We work as a team."
Lt Col Steven Jeffery, a consultant plastic surgeon, echoes his words.
"We have learned from our mistakes and there were teething problems initially, so we examined where things could be improved. We always learn in times of warfare - and this war is no exception."
He says medical staff are now dealing with wounds not seen before in other conflicts, because patients with similar injuries would simply have died on the battlefield just five or 10 years ago. However, Lt Col Jeffery warns that is also creating a need for lifelong medical care for many of the most severely-injured.
"They will develop problems throughout their lives, and we know that if you have an amputation and walk on a prosthesis you do develop problems further up the chain, so these guys will have to continue being looked after in some way for the rest of their lives."
Nurses on the critical care ward and the military-run ward say that dealing with the very public criticism in earlier years was not easy.
"It was demoralising," says sister Vicky Mulleady, who has worked at Selly Oak for nine years.
"I think things have changed and moved on since then. When patients come back to see us, we often don't recognise them because they look so well and healthy and - as a nurse - that is very rewarding."
Erica Perkins, a civilian senior critical care nurse, recently spent three months working at Camp Bastion.
"It was a very different experience for me. I don't have a military background, and so for me living in a tent for three months was quite a change. The temperatures these guys work in is incredible, and I am full of admiration for what they do."
Julie Moore, chief executive of the University Hospital Birmingham, agrees that taking care of military patients was a learning experience for both sides.
"Initially we had to learn about the military world and they had to learn about ours, but the two work very well together," she says, standing in front of the ultra-modern Selly Oak hospital buildings being built not far from the old Victorian hospital site.
She has been impressed above all, though, by the sheer courage and determination of the young men and women being treated for some of the severest injuries the hospital has ever seen.
"I think that when people see the traumas these young men and women go through, public support for our military will grow stronger.
"These are very brave young men and women going out to do what Britain asks of them, and we need to support them."
Wounded will be broadcast in two parts on BBC One on Wednesday 23 September, at 2100 BST and then at 2235 BST.