The DUP's Sammy Wilson has announced his support for Ukip's Brexit campaign, turning his back on the Tory agenda for EU reform.
The Democratic Unionist Party released a picture today of Sammy Wilson MP shaking hands with Nigel Farage at a "leave the EU" event.
A statement from Mr Wilson blasted David Cameron's case to reform the UK's membership of the European Union.
"It is evident from the pathetic demand for minimal changes to the terms of our membership of the EU, that the Prime Minister was not serious about ensuring that the UK got a better deal from Europe and the only course of action was to negotiate a relationship which fell short of EU membership," he said.
The East Antrim MP has gone against party policy, which the DUP was quick to point out remains "as in the last manifesto".
A spokesman said "we support renegotiation - were that not to be successful then we would support a vote to leave".
Ukip leader Farage is leading a campaign to vote against membership in the referendum, which is due to be held next year.
Mr Wilson said: "We need to have control over our own destiny, to determine our own laws and to protect businesses and families from the financial burdens imposed by the EU membership.
"Currently 65% of our laws are made and imposed from the EU commission with no accountability. Our membership costs this country £12bn each year, and we have a trade deficit with Europe of over £70bn at the same time we are prevented from making our own trade agreements with those countries in the world which are growing and are tied to the trade policies of the stagnating European economies.
"It is time for a change. We can have the best of both worlds, access to the European market but freedom to determine our own laws and trading arrangements. There are those who argue that being outside the EU would disadvantage us economically. They said the same thing about our decision not to joint the Eurozone. They were wrong on that issue and they are equally wrong on the question of EU membership.
"Given the determination of the majority of EU institutions and the heads of the major states in Europe to forge a federal Europe in which all countries would be corralled into a one size fits all Europe super-state, the UK would be better off out."
David McNarry MLA, the Ukip leader in Northern Ireland, said his party will work with anyone to get out of the EU, but asked: "Are the DUP in disarray over the Brexit campaign?"
"At our regional conference at the weekend, I called for DUP to quit fence-sitting on the issue of leaving the EU. The person we now need to hear from is Diane Dodds MEP. Is she still tethered to the fence, while Sammy Wilson has jumped over it?"