1. Membership fees
Does it worth paying 36 Million daily to stay in EU?
Leaving the EU would result in an immediate cost saving, as the country would no longer contribute to the EU budget. Last year, Britain paid in £13bn, but it also received £4.5bn worth of spending, says 'so the UK's net contribution was £8.5bn'. That's about 7 per cent of what the Government spends on the NHS each year.
What's harder to determine is whether the financial advantages of EU membership, such as free trade and inward investment
Will Britons benefit from an equivalent right to live and work anywhere else in the EU?
Under EU law, Britain cannot prevent anyone from another member state coming to live in the country – while Britons benefit from an equivalent right to live and work anywhere else in the EU. The result has been a huge increase in immigration into Britain, particularly from eastern and southern Europe.
According to the Office for National Statistics, there are 942,000 eastern Europeans, Romanians and Bulgarians working in the UK, along with 791,000 western Europeans – and 2.93m workers from outside the EU. China and India are the biggest source of foreign workers in the UK.
Inners say that, while the recent pace of immigration has led to some difficulties with housing and service provision, the net effect has been overwhelmingly positive. By contrast, Farage says immigration should be cut dramatically, and the leaving the EU is the only way to 'regain control of our borders'. Other pro-Brexit campaigners would not necessarily reduce immigration, but say that it should be up to the British Government to set the rules.
David Cameron says that concessions he won during the renegotiation of Britain's EU membership will reduce immigration as new arrivals will receive a lower rate of child benefit.
Would Britons be safer a lone?
Work and Pensions Secretary Iain Duncan Smith, who has come out in favour of Brexit, says we are leaving the 'door open' to terrorist attacks by remaining in the EU. 'This open border does not allow us to check and control people,' he says.
However, a dozen senior military figures, including former chiefs of defence staff Lord Bramall and Jock Stirrup, say the opposite. In a letter released by No 10, they argue that the EU is an 'increasingly important pillar of our security', especially at a time of instability in the Middle East and in the face of 'resurgent Russian nationalism and aggression'.
Defence Secretary Michael Fallon has also said the UK benefits from being part Europe, as well as Nato and the United Nations. 'It is through the EU that you exchange criminal records and passenger records and work together on counter-terrorism,' he said. 'We need the collective weight of the EU when you are dealing with Russian aggression or terrorism.'
In contrast, Colonel Richard Kemp, writing in The Times, says these 'critical bilateral relationships' would persist regardless of membership, and that it is 'absurd' to suggest that the EU would put its own citizens, or the UK's, at greater risk by reducing cooperation in the event of Brexit.
'By leaving, we will again be able to determine who does and does not enter the UK,' says Kemp, a former head of the international terrorism team at the Cabinet Office. 'Failure to do so significantly increases the terrorist threat here, endangers our people and is a betrayal of this country.'
Will the number of available jobs increase?
The effect of leaving the EU on British jobs depends on a complex interplay of the factors above: trade, investment and immigration.
Pro-EU campaigners have suggested that three million jobs could be lost if Britain goes it alone. However, while 'figures from the early 2000s suggest around three million jobs are linked to trade with the European Union,' says Full Fact, 'They dont say they are dependent on the UK being an EU member.'
If trade and investment fell post-Brexit, then some of these jobs would be lost – but if they rose, then new jobs would be created.
A drop in immigration would, all else being equal, mean more jobs for the people who remained, but labour shortages could also hold back the economy, reducing its potential for growth.
Stuart Rose, former Marks & Spencer chief executive and a prominent pro-EU campaigner, conceded recently that wages may rise if Britain leaves – which would be good for workers, but less so for their employers.
Writing for the London School of Economics, Professor Adrian Favell says limiting freedom of movement would deter the 'brightest and the best' of the continent from coming to Britain and reduce the pool of candidates employers can choose from.
Free movement of people across the EU also opens up job opportunities for British workers seeking to work elsewhere in Europe.
Will EU offer better terms?
For Brexiters, sovereignty may seem to be a simple win: few disagree that EU membership involves giving up some control over our own affairs.
Labour MP Kate Hoey says the EU is 'an attempt to replace the democratic power of the people with a permanent administration in the interests of big business.' Those on the right of the Conservative party may disagree with her emphasis, but they agree that EU institutions have drained power from the British Parliament.
'The trouble is that most of us have no clue as to how the Brussels monolith works, or who's in charge, the Connell Guide to the EU referendum. But, it says, we have only ourselves to blame. 'We've made it that way' because too many of us 'can't be bothered to vote' in European elections.
For those in the Remain camp, EU membership involves a worthwhile trade of sovereignty for influence: in return for agreeing to abide by EU rules, Britain has a seat around the table at which they are set - and, say campaigners, its voice is amplified on the world stage as a result.
'The truth is that pulling up the drawbridge and quitting the EU will not enhance our national sovereignty,' says shadow foreign secretary Hilary Benn. 'All it would do is to weaken it by taking away our power to influence events in an ever more complex and interdependent world.'
Nor, they say, would UK sovereignty be absolute if the country withdrew from the EU: the British government would still be bound by membership of Nato, the UN, the World Trade Organization, and various treaties and agreements with other nations.