Why is the referendum taking place? There is a charitable interpretation, and more realistic/cynical possibility:
Lenient interpretation: The crisis in the euro area, and the steep increase in immigration, made the public question the United Kingdom’s links with the continent more than before.
The skeptical take: It's all about optics. A symbolic renegotiation was motivated by internal political competition in Britain.
This timeline was originally published on the website of the Peterson Institute.
What to expect?
Polling is viewed with suspicion in the UK after it failed to predict the result of last year’s general election, but recent polls suggest the referendum could be extremely close.
Members of Cameron’s own government will be allowed to campaign for Britain’s exit – or “Brexit” – in a departure from the traditional principle of collective responsibility.