DENTIST Keith Morgan had no idea when he decided to enter the New York marathon that later that year he would make a life-saving donation to a teenager from the city.

Even more incredibly, the 17-year-old girl had leukaemia and Mr Morgan was running to raise money for a charity helping children with the illness.

His journey began after he said he would run a marathon if his wife Debbie completed the London event in April.

"She did finish and I had to put my feet where my mouth was," said 45-year-old Mr Morgan, who works in Newport and Cwmbran.

He agreed to enter the world-famous marathon in the Big Apple with his friend Leighton Griffiths, director of Specsavers in Newport.

They looked around for charities who could guarantee them a place in the run.

"I chose Children with Leukaemia which was based in London because 23 years ago when I was a recently qualified houseman I worked one day a week at Llandough Hospital and treated kids with leukaemia."

About a month after he started training for the run, Mr Morgan received a phone call in work from the Welsh Bone Marrow Registry.

"They asked if I remembered putting my name on the list to become a donor but I had forgotten all about it," he said.

"They had traced me because I had come up as a potential donor."

He had blood tests and in June was told he was the best match in the world for someone needing a transplant.

All he was told was that it was a 17-year-old girl with leukaemia who lived in America. His bone marrow was harvested during a three-hour operation at the Bupa hospital in Cardiff.

"It was okay, not as bad as I thought it would be and I didn't need any painkillers."

In another twist he also learnt, unofficially, that the teenager lived in New York.

In November, Mr Morgan went to the Big Apple to take part in the marathon. "I could have run past their front door and they wouldn't have known it," he said.

His efforts meant a £2,330 boost for Children with Leukaemia.

Mr Morgan received a letter of gratitude from the teenager's mum and received an update on her good progress so far.