UK citizens, by and large, did not enter the local job market [apart from dealing with UK expats and tourists] in other EU countries - there were no opportunities for them in the last 30 years.
What? I have friends who moved to Poland in 1990-1991 (when the country was in a deep economic crisis) and found plenty of opportunity there. These days, more and more Brits are turning up in PL because of the tech sector booming, combined with very favourable (as little as 5%!) taxation.
Plenty of British labourers found their fortune in West Germany, too.
but the real question is why were Brits not taking them?
The reason is simple: the welfare trap. Would you work 40 hours of smelly backbreaking work in a fish factory when you could sit at home and have 20-30 quid less to live on?
As always, people chose/were convinced to choose the easy non-solution. Instead of investing in training so that we could grow our economy we make it smaller by limiting opportunities.
One caveat: the issue with most training is that it's totally useless. I have a friend who did some Excel training provided through the Jobcentre, and he absolutely loved it. He flew through the course, and when he completed it, he went back to the Jobcentre to ask them for an intermediate course. The answer? "computer says no", as in there was simply nothing for him.
The pillock dealing with him didn't even understand that an accountancy course was a logical progression, and of course, with only basic Excel skills, he wasn't employable. The logical state of affairs, that the jobcentre fund him to do an intermediate course, was simply ruled out because the computer didn't offer it. Meanwhile, the jobcentre kept sending him for interviews for physical, backbreaking work, and my friend intentionally ruined every interview because he had no interest in doing it.
for some East European countries, life on British unemployment welfare was an improvement in prosperity compared to their wage earnings in their native countries
Where were they getting British unemployment welfare from? They certainly couldn't just turn up and claim it!