Thus folding immigration and the NHS, the top two issues according to the British public, into the Brexit debate. It was a lie, of course. Turkey is nowhere near joining the EU, and even if it applied, every single EU member could veto it should they so wish. In fact, overall, EU migrants to the UK make a net contribution to the economy, both being more liable to pay taxes to the state and being less liable to claim benefits of any kind, including NHS burden. But Leave, as was their wont, lied on pretty much everything to get the vote over the line, and once they'd reached their goal, redefined the debate away from immigration and the NHS and claimed it was all about sovereignty. If you want to see for yourself,
here are the Mori archives.
Here's OpenDemocracy's report on the Leave campaign and their use of anti-immigration adverts.