There is unregulated immigration from EU.
That statement is being debated, with some claiming it's true, and some taking the contrary position.
Maybe people are arguing semantics (without making it clear what it is they say is untrue).
There is not unregulated immigration from EU. We are currently part of the EU so there cannot be immigration "from EU" to UK.
That there is unregulated transfer of workers from certain states of the EU to the UK is (I believe) true.