Brexit: Questions and answers
Q: What is the referendum about?
A: On June 23 voters will be asked to decide whether the UK should remain part of the European Union.
If voters opt for Brexit, the UK would become the first state ever to leave the union.
Q: Why do some want to leave?
A: Anti-EU campaigners claim we pay billions of pounds a year in membership fees for little in return.
They also want Britain to take back full control of its borders and reduce the number of people coming here to work.
Q: So why do others want to stay?
A: Supporters believe the UK gets a big boost from EU membership - it makes selling things to other EU countries easier. They also believe Britain's status in the world would be damaged by leaving.
According to David Cameron and Home Secretary Theresa May, the UK is safer from terrorism inside the EU than out.
Q: What do our politicians say?
A: First Minister Arlene Foster said the DUP will recommend a vote to leave the EU.
Sinn Fein, the SDLP and the Alliance Party will campaign to stay in.
The Ulster Unionist Party is still considering its position.
Q: And how are the parties split nationally?
A: Mr Cameron wants Britain to stay in the EU, now he has got some powers back from it.
He has the backing of 23 of his 29 cabinet ministers, plus most of the Labour party and the Liberal Democrats.
The SNP and Plaid Cymru also support staying in.
Q: But not all Mr Cameron's team are behind him?
A: No. Northern Ireland Secretary Theresa Villiers is among six cabinet ministers who have declared they will campaign for the UK to leave.
Q: What would it mean for us?
A: Deputy First Minister Martin McGuinness said the implications of a Brexit would be "absolutely enormous".
Our land border with the Republic could be a major issue, given the desire in Europe to tighten borders.
Mr McGuinness also questioned how a withdrawal would affect agreements made during the peace process.
However, DUP MP Nigel Dodds said Northern Ireland would benefit from a UK exit.