A 12-year-old girl has rescued her soldier brother from the hardest battle he has had to fight - against leukaemia.

Royal Engineer Lee Robson, 24, was diagnosed with leukaemia last year. After four painful courses of chemotherapy, doctors decided his best hope of survival would be a bone marrow transplant.

All four of his sisters - Shauna, 26, Emma, 21, Lucy, 16 and Rebekka, aged just 11 at the time - volunteered to be tested.

Both Rebekka and Shauna came back as a good match. But Shauna was pregnant and unable to undergo the operation, so young Rebekka stepped in.

The life-saving transplant took place last October in the Royal Victoria Infirmary, in Newcastle. After overcoming some serious complications, Lee is now making a good recovery at his home in Leadgate, near Consett.

He praised his youngest sister for her bravery. "I think she has been brilliant," he said. "It didn't faze her at all and she took it all in her stride."

Despite her young age, Rebekka gave the full amount of bone marrow that an adult donor would give - three times the level normally taken from a child.

"They went into my hip, which is the biggest bone in the body and has the most marrow," she said.

"They normally only take ten per cent of it from a child, but I am big for my age, so I gave the adult rate, which is 30 per cent. I knew what it was all about and didn't have to think about it. He is my brother, so I could hardly say no!"

She had to take a month off school before the transplant took place in October 2002, to make sure she didn't pick up any illness or infection from other pupils that could be passed on to her brother through her marrow.

Lee fell sick in January last year, just after winning the Royal Engineers' Craftsman of the Year award for his work as a fitting machinist and returning to his barracks in Kent, following a tour of duty in Kenya with 61 Field Support Squadron - which is now in Kuwait.

A trip to the doctor's for a blood test confirmed the worst and he was diagnosed with acute myeloid leukaemia in February 2002.

"I had been back for about a week when I started feeling ill," he said.

"At first, I put it down to just re-acclimatising, but as much as I was training and working hard, I wasn't getting any fitter. The blood tests showed I was anaemic and further tests showed I had leukaemia.

The chemotherapy had its dangers. "I had a central line plugged directly into my chest," he said.

"It is the easiest way for them to administer the drugs, but is very prone to infection. These can be potentially fatal, especially as you have got no immune system to fight them off.

"I had four or five infections and was in hospital a few times with them. I was surprised when the doctors suggested a transplant, but they said I had a better chance of staying in remission."

He had to undergo a further painful treatment before the operation. "The chemo had brought my blood count back up and I was feeling well, but you have to have conditioning treatment to kill off what is left of your immune system before the operation and that left me with a pretty nasty side-effect. The drugs stripped the wall of my bladder and I was passing blood."

He faced further battles even after the operation. "After any sort of transplant, you can get a reaction of graft versus host, where the body tries to reject the new material and unfortunately I got that as well.

"They put me on steroids to help and they seem to have done the trick.

"The hardest thing has been to keep motivated and I have got my family and my girlfriend to thank for that."

His girlfriend, Susan Smith, left her home in Maidstone, Kent, last year and made the 310-mile trip to the North-East to be with Lee. He has also had visits from his friends in the regiment.

"The lads in my unit and the Army in general have been really supportive. There have been loads of phone calls and visits."

His father, Billy Robson, said: "From a father's point of view, I felt helpless - I wanted someone to blame. Usually, if something is wrong with one of the kids, you can do something about it, but I couldn't do anything apart from give Lee my support.

"This has been a really traumatic time for us all. They say these things are sent to test you and by God, it did. It has brought our family closer together and Sue moving up here and standing by Lee has been wonderful."

Lee stepped forward to tell his story to mark the launch of a nationwide campaign by the National Blood Service (NBS), aiming to thank donors across the UK for their life-saving work.

"I really am grateful for all my family's support and my girlfriend and the staff at the hospital. It was them that got me through this."

The campaign will also encourage people to become bone marrow donors.

For details on becoming a bone marrow or blood donor, contact the NBS helpline, on 08457 711711 or visit the website www.blood.co.uk