Hundreds of lives could be saved each year under a new opt-out system for organ donation approved by MPs.
Under the plans, passed by the Commons, adults in England will be presumed to be donors unless they have specifically recorded their decision not to be.
A high-profile media campaign to change the law was inspired by the case of 10-year-old Max Johnson, who was saved by a heart transplant.
If passed by the Lords, the measures would come into effect in spring 2020.
More than 5,000 people are currently waiting for an organ transplant and ministers estimate that the change in the law would save up to 700 lives each year.