Foster says DUP is ready to campaign for Brexit
Referendum on June 23 will decide whether the UK is to leave the EU
The Democratic Unionist Party has formally announced its intention to campaign for a Brexit.
The anticipated move from DUP leader and Stormont First Minister Arlene Foster came in the wake of David Cameron's referendum announcement. Northern Ireland Secretary Theresa Villiers has also joined those advocating an exit from the European Union.
The other three parties in the Stormont Executive - Sinn Fein, the SDLP and the Alliance party - all support the UK staying within the EU.
The Ulster Unionist Party, which quit the power-sharing coalition administration in Belfast last year, has yet to nail its colours to the mast. Mrs Foster said individual members of her party would be free to take opposing sides.
"The DUP has always been Eurosceptic in its outlook," she said. "At every stage in this negotiation process we had hoped to see a fundamental change to our relationship with Europe. In our view we see nothing in this deal that changes our outlook. Therefore we will on balance recommend a vote to leave the EU.
"Importantly however the decision on whether the UK should remain in or leave the EU is fundamentally not one for parties, but for every individual voter across the nation to determine.
SDLP leader Colum Eastwood said: "This campaign will be one of the most important votes faced by people in Northern Ireland in decades.
"It is therefore vital that a strong and positive campaign is conducted to remain in Europe."
He added: "Secretary of State Theresa Villiers has today joined the Leave Campaign. As I have told her repeatedly, she does not represent Northern Ireland in this position. She must not attempt to speak on our behalf.
Already six UK ministers signalled their intention to campaign for Britain to leave the European Union in the June 23 referendum by going straight from a cabinet meeting to the headquarters of the Vote Leave campaign group.
Michael Gove, Iain Duncan Smith and Chris Grayling, the leader of the House of Commons, were among the six who featured in a picture tweeted by Vote Leave holding a banner reading "Let's take back control". They were joined by Culture Secretary John Whittingdale, Theresa Villiers and Employment Minister Priti Patel.
The move by the six ministers underscores the divisions over Europe that have long riven Cameron's Conservatives, helping bring down the party's previous two prime ministers, Margaret Thatcher and John Major.
In an effort to avert cabinet resignations, Cameron told MPs in January that ministers would not be disciplined for opposing the official line on the referendum. Cameron followed up his dispensation with a letter to ministers telling them they weren't free to break ranks until after his renegotiation had been completed.
Polls on the outcome of the referendum have been inconclusive, with most telephone polls showing leads for staying in of more than 10 percentage points, and more frequent online surveys showing the 'Leave' vote ahead at times.
A poll on February 17 found that after Cameron, it's the London mayor Boris Johnson's stance on the referendum that matters the most to voters. Some 44pc of people surveyed said the PM's views will be important when making their decision, with Johnson on 32pc.
Johnson's stance may affect the currency markets, Morgan Stanley said on Friday in a note to investors. "Should the popular mayor of London throw his hat into the ring and support the no vote camp then GBP should come under immediate pressure," the bank said.
"I'm going to wait until the Prime Minister does his deal and I will then come off the fence with deafening éclat," Johnson said on the BBC.
UK ministers must usually abide by the principle of collective responsibility, which means supporting the government's position even if they have doubts.