Bereaved families have overruled the wishes of 547 registered organ donors since 2010, new figures show, blocking one in seven intended donations.
Their decisions meant 1,200 patients were denied transplants, says NHS Blood and Transport (NHSBT). There are 6,578 people in the UK waiting for organs.
Today's news comes as NHSBT announces changes to the way it handles donations. From now on, families of registered donors will no longer be asked for their consent but will instead be told they can object and how to do so.
The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
SUBSCRIBE & SAVE
Sign up for The Week's Free Newsletters
Join more than 350,000 subscribers and keep yourself informed with a selection of The Week’s most interesting, enlightening and entertaining stories - plus daily puzzles.
Join more than 350,000 subscribers and keep yourself informed with a selection of The Week’s most interesting, enlightening and entertaining stories - plus daily puzzles.
Latest Videos FromThe Week
"We are taking a tougher approach, but also a more honest approach," said NHSBT head Sally Johnson.
"My nurses are speaking for the person who has died. People who join the register want and expect to become organ donors. We do not want to let them down.
James Hardie, a specialist nurse in organ donation in London, told the BBC that families are often surprised to find their loved one had a donor card. This made them feel they did not know the deceased as well as they thought and their distress at times led them to refuse permission.
The new system, said Johnson, would help ease the grief of families, who the NHSBT has "every sympathy for".
She said: "We think this will make what is a hugely distressing day easier for them by reducing the burden on them.
"The principle that the individual affected is the one who consents applies throughout medicine and it is not different because someone has died," she added.
Last month, Wales changed its system for organ donations, switching to "presumed content" where people are deemed donors unless they have specifically opted out.
