I get your dislike of Brexit (and such sentiments get votes on HN) but this isn’t ‘friction because of Brexit’ - a post Brexit government could choose to not do this at all, or choose to implement something better.
It’s just an implementation of a crappy idea by a crappy government.
Setting aside Brexit itself, the government currently in power were elected partly on promises to cut such friction, not increase it.
But yeah, it's a crappy, incompetent government who are currently announcing all kinds of badly thought out populist ideas to distract attention from the trouble their leader is in.
It’s just an implementation of a crappy idea by a crappy government.