This year, as we have done in all recent Westminster and Stormont elections, the News Letter carried out an exit poll at Elmgrove Primary School.
The polling station is a bellwether that tends to reflect the constituency as a whole, and when in 2010 we found that Naomi Long was running Peter Robinson neck and neck there, and published that finding at 10pm as polls closed that year, it was the first published indication that the then DUP leader had lost his seat.
Since then all exit polls at Elmgrove have given a good indication of the result in the constituency as a whole.
So when on Thursday (see findings below) we found a huge margin for Gavin Robinson, of 174 exit poll votes to 91 for Naomi Long, it was so far removed from our previous findings at Elmgrove that we wondered if it was wrong as we published it online at 10pm when polls closed.
Mr Robinson was so far out in front that it suggested he would win the seat overall by a margin of at least 8,000 votes over the Alliance Party leader.
This seemed hard to believe in a contest between the same two people that had a margin of 2,600 votes in 2010 and was seen by bookies and pundits as being neck and neck this time.
But it was exactly what happened: Mr Robinson won by a margin of 8,500 votes. To a huge extent unionist voters rallied round the DUP man.
Ulster Unionists, many of whom backed Ms Long in 2010, voted DUP except for a core that voted UUP.
And the News Letter exit poll found a small number of former Alliance voters in 2015 who had voted DUP this time out of desire to send a message to Sinn Fein.
The result is a huge victory for the DUP and a major blow to Alliance in its biggest Westminster hope, which it tried to so hard to win back.
The seat now seems safe for Mr Robinson. Even with two unionist candidates in the field he won it easily.
“Wow, what a result,” Mr Robinson said, to cheers from Union Flag-waving supporters inside the Belfast count centre at 3am on Friday morning. “I wouldn’t be standing here if it wasn’t for the fantastic support I received from my team.”
Mr Robinson was criticised for the triumphalist tone of his acceptance speech in his 2015 victory. He struck a much more conciliatory note as he celebrated his second Westminster win, crediting his opponents for conducting an “enjoyable and fair campaign” and pointedly shaking hands with Mrs Long in front of the podium.
Mr Robinson said he and party colleagues would work to secure the best possible deal for Northern Ireland as the UK leaves the EU. “As we watch the television screens and we watch the reports coming from Great Britain, you just see how important it is that we have a strong voice from Northern Ireland in Westminster,” he said.
Later he told the News Letter: “I am delighted. I didn’t think it would be as close as people suggested but I didn’t think it would be as strong as it was. Some pundits have been proven wrong and some bookies are out a few quid.”
He added: “I am looking forward to getting back to Westminster.”
• Gavin Robinson (DUP): 23,917 (55.8%)
• Naomi Long (Alliance): 15,443 (36.0%)
• Hazel Legge (UUP): 1,408 (3.3%)
• Mairead O’Donnell (Sinn Fein): 894 (2.1%)
• Georgina Milne (Green Party): 561 (1.3%)
• Sheila Bodel (Conservatives): 446 (1.0%)
• Seamas de Faoite (SDLP): 167 (0.4%)
• Bobby Beck (Independent): 54 (0.1%)
Electorate: 63,495, Turnout: 42,994 (67.71%), Combined unionist vote: 60.1%