After the atrocities from last night, there are pleas to donate blood. There will be services set up to do this.
At this point I can’t give info as to where, but I’m sure you can Google.

Thanks

You can give blood any where, not just Manchester, still all has to have the same checks etc, so blood will come from all over the country, just national stock piles will be lower.

https://twitter.com/GiveBloodNHS?lang=en

Summary – don’t just turn up, but please keep your pre-arranged appointment if you have one.