Rev William McCrea declared he was leaving office with “dignity, integrity and great pride” after rival Danny Kinahan swept to victory in South Antrim.
Supporters of Mr Kinahan roared and burst in to a rendition of “For He’s a Jolly Good Fellow” after he edged ahead to oust the veteran DUP figure.
Rev McCrea had first been elected an MP in 1983; then for the constituency of Mid Ulster.
He was elected to South Antrim in 2005, and cut a sombre figure in the early hours of Friday morning as he prepared to say goodbye to his role in the constituency, telling Mr Kinahan that the UUP man would soon be embarking on a “tremendous” and “onerous” task.
It will be Mr Kinahan’s first stint in the House of Commons.
His win came after a tense night at the Valley Leisure Centre counting station, with Mr Kinahan initially saying that he and Rev McCrea appeared to be facing a “neck and neck” contest.
The UUP supporters’ singing in particular may have had a bitter sting for the DUP stalwart.
A year ago, as Diane Dodds triumphed at the European elections in the King’s Hall, he himself had led his own party colleagues in an impromptu rendition of ‘There’ll Always Be An Ulster’, ushering in her own victory.
Launching into a speech conceding defeat, Rev McCrea said: “It has been my honour and privilege to serve the people of South Antrim in the past 10 years.
“I mean that from the depths of my heart. I’ve met some of the most wonderful people in the world.
“And it’s been a joy and a privilege to serve them in every capacity, and every way, I possibly could.”
He said that at the time he became its MP, that the constituency “did not have the record it has today”.
He told the audience of reporters, party faithful and political rivals, that today the region has the lowest jobless claimant count and the highest employment rate, adding: “I do believe South Antrim will go from strength to strength.”
He also branded being an MP “a tremendous task, an onerous task” – but said that his staff had provided diligent and professional help to the residents of the constituency through his tenure.
“Therefore,” he concluded, “I will be able to leave it with dignity, with integrity, and with great pride; honouring the people that I was honoured to serve.”
Nationalist candidates, as predicted, made little impact.
But the Alliance Party performed well, growing its vote on last time.
This may have come as a welcome surprise to leader David Ford, who had told the News Letter during the counting process that he expected the relatively liberal Mr Kinahan would “squeeze” their vote.
• Danny Kinahan (UUP): 11,942
32.5pc, up 2.1pc on 2010
• William McCrea (DUP): 10,993
29.9pc, down 4pc
• Declan Kearney (Sinn Fein): 4,699
12.8pc, down 1.1pc
• Neil Kelly (Alliance): 3,576
9.7pc, up 2pc
• Roisin Lynch (SDLP): 2,990
8.1pc, down 0.6pc
• Richard Cairns (TUV): 1,908
5.2pc, down 0.2pc
• Alan Dunlop (Con): 415