I'm guessing all of them or they wouldn't have been working here in the first place.
Well, nearly all, I'm not disputing this.

But, rather than be sensible and declare HGV drivers a shortage occupation, the gov't is kowtowing to anti-immigration zealots amongst their supporters who did vote Brexit to stop immigration. Seems a bit retarded imo.
Well on this we can agree. It's retarded because as best as I can tell, the vast majority of people who have any sort of problem with immigration tend to oppose Islamic immigration or uneducated migrants fleeing France by any means possible, not Polish lorry drivers who are here legally and are paying UK tax. Yes there are a small number of people who just don't like any kind of foreigner, but genuinely, this is a small demographic.

Not sure why Boris would feel the need to appease such people, it's not going to swing an election.