Next year the law on organ donations in England will change, with donor consent being presumed, unless relatives expressly refuse permission.
This is already the law in Wales. More than 50,000 people today are alive thanks to organ donations, but 400 die every year while waiting for a transplant.
Despite this, 4 in 10 families still refuse to allow a donation.
BBC News spoke to some of the doctors and nurses who help bereaved people reach their decision.