By Duncan Middleton
The NHS Organ Donor Register has been in operation since 1994
Have a quick look in your wallet. Amongst all your store and credit cards, have you got one saying you're an organ donor?
Hundreds of people in the UK die every year waiting for a transplant.
Although more people than ever are signing up, doctors say it's still not enough.
When Alexandra Burke won X Factor last year, she spoke about her mum, Melissa Bell, who desperately needs a kidney transplant. She has to have dialysis three times a week.
"Just to put things into perspective, if I miss any two of those three sessions I will die by the third session," said Melissa.
"Diabetes runs in my family. My mother passed away waiting for a kidney," she added.
Almost 8,000 people in the UK are waiting for life-saving transplants. But because of a lack of donors, many will die before they get help.
"Three people a day are still dying waiting for a kidney or another organ," says Lynda Hamlyn, Chief Executive of the NHS Blood and Transplant Authority, "and we just can't let that happen."
For the first time, the number of people on the organ donor register has topped 16 million - doctors insist many more are needed, though.
'Very, very crucial'
"We're appealing to everyone who's already on the list, go and ask your friends and family to be on the list," said Lynda.
Organs for transplant are transported in boxes like this
"Make sure you tell your family that you are on the list so your wishes are respected if it ever came to that."
Justine Laymond had a double lung transplant two-and-a-half years ago.
"It's very, very crucial," she said, "and I'm so grateful and very emotional with how my life has changed since the donation of my lungs."
She knows that many people still feel weird about becoming a donor, but says there's no need to think that.
"One person can save up to seven people's lives. You don't want anyone to die to save your life but I do believe, when your body is at rest, there is no need to have your organs going to heaven."