A caring Keighley mum has offered to give her dying cousin part of a lung in a bid to save his life.

The 56-year-old mother-of-two made the poignant pledge as soon as she learned of her relative's desperate plight.

But builder John Spencer -- who has been told by doctors that he could have just two months to live without a transplant -- has turned down the offer.

John, 57, said he was moved to tears by his cousin's incredible act. But he told the Keighley News that he couldn't expect her to go through surgery and put her own life at risk.

John, who is married with a 24-year-old son, was diagnosed in February last year as having a condition known as usual interstitial pneumonia.

He constantly has to take oxygen to aid his breathing.

His condition has worsened in recent months and now a lung transplant is his only hope.

John has twice been rushed into Papworth Hospital, in Cambridgeshire, when donor lungs have been found, but on both occasions the donated organs have proved to be unsuitable.

He said he was overcome by emotion when his cousin -- who has asked not to be named -- phoned him with the offer of help.

"I cried and cried," he said. "It was a remarkable thing to do.

"I contacted Papworth Hospital to discuss it and was told that the operation posed serious dangers for a live donor.

"There could be as many complications for the donor as for the recipient.

"My cousin still insists on donating, but I will not put her life in jeopardy."

Despite his failing health, John, who is known within the family by his middle name of Barry, has been campaigning vigorously to raise awareness of the need for people to register as organ donors.

He is calling for more people to carry donor cards, a sentiment echoed by his cousin.

She said: "Within our family we have made it known to each other that should anything happen, we would like our organs to be available for transplant.

"Too few people think about this.

"When I learned how ill Barry was and of his desperate need for a transplant, I could see a way of helping. You feel so helpless when you lose someone, but this was an opportunity for me to do something.

"By transplanting a lobe from my lung, it would keep him alive.

"It is not a common operation and there are serious potential dangers -- but despite Barry's reluctance to accept, my offer still stands."