An election in Lagan Valley without Jeffrey Donaldson is almost unthinkable. But the refusal of the Ulster Unionist Party leadership to allow him to stand in the Assembly elections, due to his anti-agreement stance, will make the contest in this solid unionist heartland an intriguing and less predictable affair.
The position taken by candidates in the referendum on the agreement will play a critical role here.
Lagan Valley is a constituency with a population of 107,000 and approximately 71,000 voters. It takes in Lisburn, which is the second-largest borough in Northern Ireland and also home to the Maze Prison and Hillsborough Castle, Queen Elizabeth's official residence in the North.
Lisburn is reasonably affluent and has an abundance of leisure and shopping facilities, although there are pockets of high unemployment here and elsewhere in the constituency.
The 30 members of the borough council represent a wide spectrum of political opinion, but are said to work well together on local issues.
Its rates, payable to the local authority, have been among the lowest in the North for a number of years.
Establishment unionism has always had a solid foothold here. Sir James Molyneaux was MP for Lagan Valley for 14 years and it was here that the aspiring 18-year-old Jeffrey Donaldson cut his political teeth when he joined the UUP.
At the age of 22 he became the youngest person elected to the Northern Ireland Assembly. He was chairman of the Young Unionists and personal assistant to Mr Molyneaux, the one-time leader of the UUP.
In 1992 the UUP secured 60 per cent of the votes in the Westminster election: last year, Mr Donaldson took over Mr Molyneaux's old seat, winning 55 per cent of the vote and enjoying a 17,000 majority.
But many things have changed since then, and Mr Donaldson's absence from the hustings this time makes things much more interesting.
The UUP is throwing no fewer than four candidates into the fray and is confident of winning two seats. Mr Ivan Davis, a long serving local councillor, and Mr David Campbell, who has served on the Forum, are expected to be elected safely, but there is no guarantee of a third seat.
The UUP campaign organiser in Lagan Valley, Mr David Archer, predicts that the controversy over Mr Donaldson not being allowed to stand for the party will cost it a seat.
"There is a lot of strong feeling about that here.
"When the decision was announced we were inundated with something like 700 calls from people in a few days and they may wish to register their protest by voting for other parties," he said.
The Democratic Unionist Party is licking its lips over the potential windfall.
Mr Edwin Poots, a veteran local councillor, is expected to take one seat for the DUP, and his running mate, Mr Cecil Calvert, has the chance of a second. Suddenly it is all to play for, especially for the parties which campaigned for a No vote in the referendum.
"Obviously, it is a tremendous boost for us that Jeffrey Donaldson is not standing. A number of people have already indicated that they would have voted for him, but because the other UUP candidates are on the Yes side they have no alternative but to vote for the DUP," said Mr Poots.
The leader of the UDP, Mr Gary McMichael, is a local councillor and may also have the chance of a seat in an area considered the support base for his party.
One candidate considered a certain winner in the constituency is the Alliance Party candidate, Mr Seamus Close.
First elected to Lisburn Borough Council in 1973, he is celebrating his silver jubilee as a public representative in the area. He also served on the Northern Ireland Assembly from 1982 to 1986.
In the last general election, Mr Close polled 7,635 votes - 17 per cent of the vote - and he is "quietly confident" of winning a seat.
The SDLP candidate, Ms Patricia Lewsley, is said to be a contender for a final seat, depending on the level of transfers from Sinn Fein and the Alliance Party.
Sinn Fein received 1,100 votes in the 1997 general election, representing 2.5 per cent of the vote, and will not feature in this contest.
Lagan Valley canidates:
Seamus Close (Alliance Party), Edwin Poots (DUP), Cecil Calvert (DUP), David Campbell (UUP), Ivan Davis (UUP), Kenneth Hull (UUP), Billy Bell (UUP), Patricia Lewsley (SDLP), Gary McMichael (UDP), Paul Butler (Sinn Fein), William Bleakes (Conservative) and Annie Campbell (Women's Coalition)
Westminster election 1997: UUP (55.43%), Alliance (17.23%), DUP (13.55%), SDLP (7.75%), Conservative (2.74%), SF (2.51%), WP (0.46%), NLP (0.34%).