P.S. while just registering is great, it can help to have an organ donor card in your wallet (I got mine for free when I registered via the NHS website a while ago) so there’s no confusion if they find your wallet

Also if you use Apple’s Emergency Medical ID (if you have an iPhone you should set it up now!), you can also mark yourself as an organ donor in there! Of course you still need to register properly as a donor for it to be definitely honoured