Do note that this isn't just a short link like with, say, bit.ly, but a vanity link like https://www.gov.uk/brexit-eucitizens https://www.gov.uk/brexit-eucitize

Do note that this isn't just a short link like with, say, bit.ly, but a vanity link like https://www.gov.uk/brexit-eucitizens https://www.gov.uk/brexit-eucitizens , which means you actually need to check them for validity before assigning them.