South Belfast is probably the most unpredictable result of all 18 Westminster seats in Northern Ireland.
It also has arguably the most significant five-way candidate split in any of the 650 constituencies across the whole of the United Kingdom.
It would not be entirely surprising if the seat broke a record in this election for the smallest vote share of any winning MP in a British election.
The record is currently held by Russell Johnston, who won Inverness, Nairn and Lochaber in 1992 for the Liberal Democrats with 26.0 per cent of the vote.
There are only six other MPs who have ever won election to Westminster on less than 30 per cent of the vote in their constituency.
Alasdair McDonnell is the favourite to retain South Belfast, but if the SDLP leader does secure re-election, he will not do so by a large margin, such is the splintered field against him.
He, or any candidate who beats him, will probably get less than a third of the vote.
This is because there are five candidates — SDLP, Sinn Fein, DUP, UUP and Alliance — who have a plausible prospect of getting at least 5,000 votes or 15 per cent of the vote.
There are also four candidates from smaller parties — Green, Workers Party, Conservative and Ukip — who have a fair prospect of getting at least 2,000 votes between them, or around five per cent of the vote.
If those various nine candidates poll as highly as that, it becomes difficult for any one of them to get much more than 30 per cent of the votes.
Mr McDonnell won surprise election to Westminster in 2005 with a mere 32.3 per cent of the vote against a divided unionist opposition, in which the DUP’s Jimmy Spratt was 1,800 votes ahead of Michael McGimpsey’s 7,263 votes for the UUP.
The SDLP man was re-elected in 2010 with 41.0 per cent of the vote, but the increase was largely attributable to the fact that Sinn Fein stood down in a bid to keep the constituency in nationalist hands.
In that contest, the DUP increased its margin over the UUP to over 2,000 votes.
This is one reason why Peter Robinson’s party was in no mood to stand down in favour of the Ulster Unionists during the talks that led to a unionist pact in four constituencies.
But the UUP can also argue powerfully that the DUP should have given way to them in South Belfast.
While the latter party is in the ascendent in the area now, the UUP were ahead for decades and it was considered a safe seat when it was held by the Rev Robert Bradford and then, after his murder, by the Rev Martin Smyth.
In the 1983 general election the UUP got almost 19,000 votes to the DUP’s 4,500. The SDLP were on a mere 3,200 votes while Sinn Fein barely featured with 1,100.
South Belfast has undergone gradual but relentless demographic change. It has long had a large, transient student population and it now also has a much higher ethnic minority population than the rest of Northern Ireland.
The most notable change has been in the leafy suburbs, from Malone to Rosetta, which were overwhelmingly Protestant but are now mixed.
The large professional population is one reason why Alliance has always polled strongly in South Belfast.
Paula Bradshaw might struggle to match the support of Anna Lo, who is one of the party’s most electorally popular representatives, but Ms Bradshaw has a high profile working in the Village area.
The Ukip candidate Bob Stoker is also well known in this part of the constituency, having been an Ulster Unionist councillor in the ward for almost 20 years (and Lord Mayor in 1999).
He will be expecting his poll tally to be 1,000+, as will the Green candidate Clare Bailey. Conservative Ben Manton will hope to be at that level. The Greens have polled relatively well in South Belfast. The Tories have a large pool of affluent potential supporters.
One of the biggest obstacles to Dr McDonnell’s re-election is the candidacy of Máirtín O’Muilleoir for Sinn Fein, who is seen as a moderate republican. Sinn Fein will be hoping that the former Lord Mayor appeals to a large section of the growing middle-class Catholic population.
Within unionism, the junior Stormont minister Jonathan Bell suffered a hiccup when he apologised to Rev Smyth, who felt that Mr Bell had misled the former MP into signing his nomination papers. Mr McCune emerged from an internal UUP contest in which the councillor Jeff Dudgeon scored more local support, leading to the party insisting that Mr Dudgeon was not overlooked due to his long association with gay rights.
The Workers Party is fielding Lily Kerr.
BAILEY, Clare (Green Party)
BELL, Jonathan Fergus (DUP)
BRADSHAW, Paula (Alliance Party)
KERR, Lily (The Workers Party)
MANTON, Ben (Conservatives)
MCCUNE, Rodney James (UUP)
MCDONNELL, Alasdair (SDLP
Ó MUILLEOIR, Máirtín (Sinn Fein)
STOKER, Bob (Ukip)
• Alasdair McDonnell (SDLP): 14,026
41.0%, up 8.7 on 2005
• Jimmy Spratt (DUP): 8,100
23.7%, down 4.7%
• Paula Bradshaw (UUP-Con): 5,910
17.3%, down 5.4%
• Anna Lo (Alliance): 5,114
15.0%, up 1.5%
• Adam McGibbon (Green): 1,036
• A McDonnell (SDLP): 10,339, 32.3%
• Jimmy Spratt (DUP): 9,104, 28.4%
• M McGimpsey (UUP): 7,263, 22.7%
• Alex Maskey (Sinn Fein): 2,882, 9%
• Geraldine Rice (Alliance): 2,012, 6.3%
• L Gilby (Vote for Yourself): 235, 0.7%
• P Lynn (Workers Party): 193, 0.6%
• Martin Smyth (UUP): 17,008, 44.8%
• A McDonnell (SDLP): 11,609, 30.6%
• Monica McWilliams (NI Women’s Coalition): 2,968, 7.8%
• Alex Maskey (Sinn Fein): 2,894, 7.6%
• Geraldine Rice (Alliance): 2,042, 5.4%
• Dawn Purvis (PUP): 1,112, 2.9%
• P Lynn (Workers Party): 204, 0.5%
• Rainbow George Weiss (Vote for Yourself): 115, 0.3%