Colin and Chris Weir to buy Kieran Maxwell's new limb Published duration 31 July 2012

media caption Kieran Maxwell carries the torch in Bishop Auckland as crowds cheer him on

A teenager who lost a leg to cancer will have a life-changing operation after Britain's biggest lottery winners bought him a new prosthetic limb.

Kieran Maxwell from Heighington, near Darlington, had his left leg amputated last March.

Colin and Chris Weir from Ayrshire stepped in to donate part of their £161m prize after hearing about his story.

The 13-year-old carried the Olympic torch in June.

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

'Change his life'

His mother Nicola said he started "yelling and dancing" when he found about the donation.

Mrs Maxwell said: "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. Words cannot describe what they have done."

Since losing his leg, Kieran has been determined to remain active and took part in the Torch Relay as it passed through Bishop Auckland, County Durham.

image caption The Weirs have already made donations to several causes close to their heart

His family have been fundraising to buy a lighter replacement limb as Kieran's current one is heavy and restricts his movement.

The youngster stumbled to the ground when carrying the Olympic torch and was helped up before continuing.

Mr and Mrs Weir heard about Kieran's story through the grandmother of one of his friends and agreed to donate a five-figure sum.

Ewan Barr had told his grandmother, who lives near the Weirs, about Kieran's battle for a lighter leg.

She posted a letter to the couple and received a call three days later from the Weirs' assistant, offering them help.

The couple, from Largs, pledged to share their good fortune after winning the jackpot last July.