Turkey has become such a thorny issue, that its prospects of joining the EU are receding. (BBC).
EU referendum: Will Turkey's EU hopes affect UK vote?
The question of whether Turkey and six Balkan countries will join the European Union and, if so, what it will mean for the UK has become a live issue in the EU referendum campaign.Campaigners wanting to leave the EU say such a further enlargement could result in a migration "free-for-all" and pose a "serious and direct threat" to UK public services. Is there any truth in this?
Nothing will happen for at least three years, because European Commission President Jean-Claude Juncker imposed a five-year moratorium on enlargement in 2014.
Seasoned EU-watchers say Montenegro and Serbia are, to coin a phrase, at the front of the queue, while there are major hurdles to overcome with Albania, Bosnia, Kosovo and Macedonia.
As for Turkey, the challenges it faces in meeting the membership criteria are so big, and it has become such a thorny issue, that its prospects are receding.
In short, yes. Turkey has a customs union with the EU, but its troubled relations with the Republic of Cyprus have always been a unique stumbling block - a situation exacerbated by Cyprus' own admission to the EU in 2004.
Turkey would also be the first country with a majority Muslim population to join the EU, in itself a major development.
Some see a future advantage for Europe if many young Turkish workers fill jobs, as ageing populations cause the labour force to shrink.
But the migrant crisis, caused by the five-year civil war in Syria, has fueled doubts among those EU politicians who, in principle, have always been in favor of letting Turkey in.
More than two million Syrian refugees have fled to Turkey, a country which already had a population of nearly 76 million.
EU leaders are desperate to uphold free movement rules, enshrining the right of any EU national to live and work elsewhere in the union. They are nervous that admitting a country of Turkey's size could make this untenable.
Under a recent agreement with Turkey to curb the migrant influx to Greece, the EU undertook to "re-energise" the stalled accession talks.
But there are major concerns about Turkish human rights violations, including curbs on the media and rule of law - all key issues when judging a country's fitness to join the EU.
At the same time, economic hardship, Islamist terror and the migrant crisis have fuelled a nationalist backlash in much of Europe, often expressed as hostility to Islam.
Even politicians in favour of EU membership, such as Home Secretary Theresa May, have signalled that further enlargement needs to be reconsidered for countries with "poor populations and serious problems with organised crime, corruption and sometimes even terrorism".
Ministers have emphasised that the UK has the right of veto over future prospective members, while insisting the talks with Turkey and other countries are unlikely to be rushed and, as such, the issue will not come to a head for a while.Last month, George Osborne said a Turkish agreement was "not on the cards any time soon" and insisted the UK would not allow any free movement deal with countries which weren't closely aligned in terms of size and prosperity.
Hmmm......Thank God for Churchill, 'we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender'.Read the full story here.