Around 3.4 million British jobs depend upon exports to the EU, according to data from the European Institute. A Brexit would not necessarily eradicate these positions, since many commercial links would remain between the UK and the EU, but a changing relationship would likely affect employment rates within Britain.
The 100 most expensive European regulations cost Britain €46.7 billion a year, according to a March 2015 study by the Open Europe think tank. Those arguing for a Brexit say the EU regulations are a burden for British businesses. A Brexit could cut down on some of those costs, but Open Europe says it would not eliminate British regulatory spending – the UK would still need to ensure that it complied with European trade rules for all transactions with EU members.
The UK exported €288 billion in goods to other EU countries in 2014, accounting for some 45 percent of all exports, the British parliament says. Opponents of a Brexit fear that an EU exit would risk British companies losing market share in the world's largest trading block.
Some 53 percent of imports into the UK – €394 billion in goods and services – came from the European Union that same year.
An estimated 3 million EU nationals are resident in the UK and roughly two-thirds of them are employed. Some 1.3 million Britons also live elsewhere in the European Union, and at least 30,000 Britons claim unemployment benefits in EU countries, according to a January 2015 survey published in The Guardian.
The European Union is a major source of foreign investment for Britain. In 2014 the 27 other EU countries invested €620 billion (£496 billion) in Britain – 48 percent of all foreign investment in the country, according to the British parliament.
But Britain is a net contributor to the European budget – meaning it pays the EU more than it gets. In 2014 the country paid €12.3 billion more into EU coffers than it received. And although Britain’s EU budget is relatively small at only about 1 percent of GDP, the fact that Britain is a net contributor to the EU angers many Brexit supporters.