you need to really think through what would happen if you said, OK, no-one in X town can claim JSA
I spent a lot of time elaborating that I didn't actually mean no-one. I think you stopped reading to soon. Even after this measure, this town would still have higher unemployment than others, just not as high as before. (As soon as it stopped being in the worst one-fifth of towns for unemployment, the measure would stop applying.)
What would happen if you wanted to open and staff a new business?
Non-issue, see above.
What would happen to wages and working conditions in the town if employers had their staff over a barrel like that?
For my measures to continue applying, the town would have to have worse unemployment than 80% of the country. So in terms of market forces operating on employment, the measure would make no difference.
What would happen to the unemployment rate in Y town when all these jobseekers moved in? What would happen to the availability of housing/GPs/schools?
Are you really arguing that no town population can ever change, not even by 2 or 3 percent spread over a number of years? Towns change by more than that all the time.
And that's before we even start thinking about the actual, y'know, people involved, like how you afford to move to a more expensive city when you have no money, and no bugger wants to let to folks on HB.
Which is why I specifically said the cost of moving would have to be covered.
And where all the jobs would come from.
OK you've persuaded me. If you live in an area with no job vacancies, it's preferable to spend the rest of your life on benefits rather than move to where there are some.