A teenager who lost a leg to cancer "started yelling and dancing" when he heard Britain's biggest lottery prize winners have bought him a new prosthetic limb, his mother said today.

Kieran Maxwell, 13, from Heighington, near Darlington, was diagnosed with Ewing's Sarcoma, a rare and aggressive form of cancer which affects fewer than 30 children a year, in October 2010.

He had his left leg amputated below the knee in March last year despite undergoing gruelling chemotherapy.

Since losing his leg Kieran has been determined to remain active and carried the Olympic Torch last month when the relay passed through Bishop Auckland last month.

But his current replacement limb is heavy and slows him down, so his parents Nicola and Alistair decided to try to raise the cash to buy him a lighter model from the US.

kieran maxwell

Kieran, who lost his left leg beneath the knee after cancer, will be able to afford the new limb easily

Lottery winners Colin and Chris Weir from Ayrshire - who scooped £161 million in a EuroMillions draw a year ago - heard about Kieran's battle and stepped in with a five-figure donation to buy the new leg outright.

Mrs Maxwell said: "Kieran started yelling and dancing around when he heard.

"He couldn't believe it. I am still pinching myself.

"What they have done for Kieran will be a small drop in the ocean for them but for him it will change his life.

"He can go back to being a normal boy. He can be himself.

chris colin weir

The Weirs scooped £161m last year in the EuroMillions draw

"Words cannot describe what they have done."

Kieran, who has a younger sister Alyssa, is currently on a Scout camp with friends.

One of them, Ewan Barr, had told his grandmother about Kieran's battle for a lighter leg.

She lives near the Weirs, although she does not know them, and contacted them about Kieran's plight.

After posting them a letter on the Monday, she received a call on the Thursday from the Weirs' assistant, offering them help.

Kieran's parents will continue to fundraise, but will now hand over proceeds to the Toma Fund, which helps teenagers with cancer.