If you're concerned that Turkey may join the EU soon and the UK be forced to accept millions of Turkish migrants, and you want to vote Leave for this reason, then please pause and think for a moment.
If Britain votes Leave and then applies to join either the EEA or EFTA in order to maintain preferential trading relationships with EU countries, then we will have to accept free movement of people from the EU, just as Norway (EEA route) and Swtzerland (EFTA route) do already.
But, we will also relinquish the UK's veto rights in deciding who joins and does not join the EU; which might make it easier for Turkey to join.
So, if you're thinking you will vote Leave in order to keep Turkish migrants out of the UK, then please think again. A vote to leave the EU would make it MORE likely that Turkey will join the EU and the UK will have to accept Turkish migrants, not less likely.
NB: I want to make it abundantly clear here that I do not in any way agree with the sentiments of people wanting to leave the EU for the above reason. I am just pointing out - yet another - obvious inconsistency with their way of thinking.
And by the way, Turkey is already an Associate Member of the EU and has been since 1963, is a member with the UK of NATO and the OSCE, a member of the Council of Europe since 1949, and was a founding member of the OECD in 1961. Geographically Turkey is as much a European country as the UK, perhaps more so since the UK does not have any territory on the continent of Europe, unlike Turkey.