General Election June 2017

The obvious one is that EU workers are taking over jobs as they're willing to suffer worse pay/conditions and that is what has gained a lot of support for Leave.

Obviously the argument is that this isn't really an immigration issue, it's a government issue with minimum wage rules, etc. That is a bit of a race to the bottom though if the only protection is the minimum wage. You can see why a business will want to replace its unionised workers who are earning £15 an hour with immigrant labour who aren't part of the union and earns minimum wage.

It isn't really clear how this can be legislated against and maintain freedom of movement.

Strong, sensible rules protecting the rights of workers and setting a minimum per-hour figure would do so, unless I'm missing your point?

i.e. if you have to pay everyone the same, regardless of country of origin, then yes - there's a motivation for those nationalities whose economies are in worse shape than ours to come to apply for jobs, but there's no motivation for employers to favour a foreign national over a UK national.

That doesn't get round the issue of UK nationals simply not wanting those jobs, of course.