Jeffrey Donaldson

Three Ulster Unionist MPs have announced they will no longer take the party whip at Westminster.

Jeffrey Donaldson, the MP for Lagan Valley, party president Reverend Martin Smyth and South Antrim's David Burnside detailed the move on Monday.

It followed a weekend of consultations between hardline party members opposed to David Trimble's position on returning to the power sharing Stormont executive.

But in a compromise move the three MPs stopped short of resigning from the party.

"This is not about civil war. This is about the principles our party was founded on," Donaldson said at a Belfast press conference.

The MP has been a constant critic of the UUP leader's strategy.

Last week he was again narrowly defeated in an attempt to reject the latest joint declaration from the British and Irish governments.

Donaldson had described the deal as "packed with concessions to Sinn Fein's IRA".

But Trimble won the vote, securing the backing of 54 per cent of the party's ruling council.

Following that move, he appealed to Donaldson to stop undermining the party.

However, the Lagan Valley MP appears set to remain a thorn in the side of his party leader.

And the latest move means the UUP's strength at Westminster will be effectively curtailed - only Trimble and North Down MP Lady Hermon will still take the party's whip.

The three rebels set out a clear intention to continue challenging Trimble.

"We must see to it that unionism is never again represented at the negotiating table in a weak and dysfunctional state," they said.

"It is our goal to see a realignment of unionism into a cohesive and dynamic political force that will be capable of delivering political stability for all the people of Northern Ireland and securing the union for future generations."