Brexit fact check: The truth about the immigration debate

When is a referendum about membership of the EU not really about the question on the ballot paper? When it is about immigration - the most consistent theme politicians are hearing on the doorsteps and the subject which dominates debates in the run up to the June 23rd vote.

As a member of the European Union, the UK has limited control over immigrants coming from other EU countries because of the principle of free movement - a fact which frustrates many British people no end, with the perception that their ability to decide who comes and works and when is out of their hands.

But is that the case? How many EU immigrants are in the UK?

Less than people think - about 3.5 million people, about 5 per cent of the population. A recent poll showed British people think there are three times as many. Those who want to vote to leave the EU think there are four times as many as there actually are.

So are most immigrants to the UK from the EU?

Nope. According to the number crunchers at Eurostat, in 2014 the UK took in 236,600 immigrants from the EU and 287,000 from outside the EU. The UK was the second biggest recipient of immigrants, just after Germany. However, per head of population, it came 10th amongst its EU peers, behind Luxembourg, Malta, Ireland, Austria, Sweden, Denmark, Belgium, Germany and Cyprus.

But where are these immigrants coming from?

The largest population group of immigrants by citizenship is from Poland and after that India, Ireland, Pakistan and Romania.

Therefore the majority of immigration is from outside the EU. Why the debate?

One word: Control. The Leave side says that it is impossible to control immigration as a member of the EU and public services are under pressure as a result of the numbers which are coming in. Instead they want a points-based system, similar to that in Australia, where just those with the skills needed will be allowed access to the UK labour market. Energy minister Andrea Leadsom has claimed that immigration could "overwhelm" Britain. Meanwhile, Migration Watch, a group which favours lower immigration, says that net migration will exceed 250,000 a year for 20 years if there is a vote to remain.

But there are people leaving as well, right? It is not a one way street.

Last year, the Office for National Statistics said that net migration to the UK went to 333,000, the second highest figure on record and fuel for Leave’s argument.

What about Remain, what do they say?

Those in favour of staying in the EU say that immigrants pay more in taxes than they take out and that even in the case of an exit, Britain would still have to accept free movement in order to gain access to the single market.

So leaving could leave immigration the same?

Independent charity Full Fact, in one of its breakdowns of claim and counter claim, points out that one option post-Brexit would be for Britain to join the European Economic Area (EEA), along with Norway, Iceland and Liechtenstein, in order to get access to the single market. However, free movement applies to all members of the EEA. A research paper on the effects of a Brexit says that if Britain wants a Swiss-style situation of access to the single market outside of the EEA, it would probably have to accept some EU rules. What these will be depend on negotiations between the UK and the EU.

Would there be a rapid change to immigration policy after a Brexit?

Again, no one knows and many speculate. The effects of changes have been spelled out by some industry leaders however. Greencore, the Irish food producer which makes lunchtime staples such as sandwiches and wraps for supermarkets, says 4,000 of its 12,000 staff in the UK are from other EU countries. Changes to worker flow via immigration reforms would result in knock on costs to run farms and factories - in turn pushing up the price of a chicken and stuffing sandwich at lunchtime.