Ulster Unionist Party

The Ulster Unionist Party is the largest party in Northern Ireland.

A split in the party means that five of the UUP's nine MPs are opposed to the Agreement

The UUP draws its support from the unionist community, the vast majority of whom are Protestant.

Its leader David Trimble is also Northern Ireland's first minister, a post he has threatened to resign from on 1 July if the IRA do not decommission.

Internal splits

This tough threat underlines the difficulties the UUP has in continuing its official backing of the Good Friday Agreement.

Three years ago the party campaigned for a "yes" vote in the referendum held to find out how much support there was for the peace deal.

However a split in the party means that five of the UUP's nine MPs are now opposed to the Agreement.

One of these is the Lagan Valley MP Jeffrey Donaldson who is the main spokesman for the "no" camp.

In March last year the anti-Agreement camp challenged Mr Trimble's leadership.

But MP Martin Smyth lost the vote by 43% to 57%.

Uneasy pact

Martin Smyth: challenger for the leadership

The party's position on the executive has been fraught with difficulty.

For a time it refused to sit in government with Sinn Fein because the IRA had not begun to hand in its weapons.

The Secretary of State later suspended the assembly after the party threatened to collapse it over the same issue. After months of talks, the party agreed to go back into the Stormont government.

This uneasy pact is based on the assumption that the IRA is engaged in a process that will lead to decommissioning.

The speed of progress on this is a cause of huge concern within the UUP.

The party holds 28 seats in the Northern Ireland Assembly, including four ministerial posts.

However, two of its members do not take the UUP whip.

Tough battles ahead

Longstanding MPs Ken Maginnis and Deputy Leader John Taylor are standing down at this election

Peter Weir, who was the Ulster Unionists' North Down general election candidate, was suspended in February for repeatedly voting against the party line.

In the 1997 Westminster elections, the UUP won 10 of the province's 18 seats.

One of its MPs, Clifford Forsythe died and his seat in south Antrim was lost in a by-election to the Democratic Unionist Party.

David Trimble: a man under pressure within his party

Longstanding MPs Ken Maginnis and deputy leader John Taylor are standing down at this election.

The party is expected to face its toughest election battles with the Democratic Unionist Party in North Belfast and Strangford.

And the nationalist parties of the SDLP and Sinn Fein are expected to mount strong contests in west Tyrone and Fermanagh and South Tyrone.

Long tradition

The UUP was founded in 1905 when the Ulster Unionist Council was formed - it remains the UUP's ruling body today.

In 1921 Ulster Unionists formed the government of Northern Ireland after the island of Ireland was partitioned.

This was replaced by direct rule from London in 1972.

The UUP had become part of the Conservative Party but the relationship broke down when the Troubles emerged in the late 1960s and early 1970s.