A schoolgirl from Croydon whose brother had an organ transplant when he was four, has appeared on Channel 4 to highlight her campaign to encourage others to become donors.

Hope Milne's brother William, now 7, had a small bowel transplant in 2008 and the organ was donated by a 14-year-old girl.

The 15-year-old has set up a campaign with Abby Thackery, 21, from West Ewell, whose sister had a double lung transplant in 2007, to encourage more people to join the organ donor register.

The Sign Up and Save a Life campaign is being backed by X-Factor winner Alexandra Burke, whose mother is waiting for a kidney transplant.

The girls promoted their campaign last weekend on the Channel 4 series Battlefront, which highlights campaigns being run by young people.

Hope said: "I feel so passionate about it not only because it has affected me personally, but because I know that it can make such a difference and can save so many lives.

"I have known people who have died waiting for a transplant, so I decided to set up a campaign to get more people to join the organ donor register.

"Our main goal is to get people talking about organ donations, to sit down with their families and discuss their wishes."

Hope wants the campaign's appearance on Battlefront to increase the number of people talking about organ donation and hopes it boosts the number of people signing up to be organ donors.

She said: "The experience of being a Battlefront campaigner is amazing, I have already acquired so many tips and skills on successful campaigning.

"Battlefront is an important project because it can turn small campaigns into huge ones and let viewers see young people making a difference in a positive way."

For more information on becoming an organ donor visit www.uktransplant.org.uk