The DUP’s Sammy Wilson told other unionist parties they “ought to be ashamed” as he was re-elected to East Antrim with 28.9% of the vote.
Mr Wilson retained the seat he has held for 19 years with 11,462 votes, but with a majority of just 1,306 votes over his nearest rival Danny Donnelly of the Alliance Party.
The DUP saw a significant drop in its vote share on five years ago.
In his acceptance speech, Mr Wilson said: “There are seats which will be occupied in Westminster for the next five years by someone who is opposed to many of the unionist ideals which I adhere to. They didn’t need to be lost. They could have been won had the unionist vote not been split.
“My message to you is, ‘You ought to be ashamed; you knew what you were doing. In fact, in some cases, you made it quite clear that your chief objective was to destroy another unionist party rather than to ensure that the Union was secured’.
“I hope that in the days to come unionists will learn that, if we want to have the kind of representation at Westminster that we deserve, then we must act together – not act against each other.”
The Ulster Unionists fielded high-profile Stormont Assembly member John Stewart, who polled 23.9% of the vote (9,476), up from 2019. The Traditional Unionist Voice (TUV) candidate Matthew Warwick came fourth, receiving 10.4% of the vote on 4,135 votes.
Reform UK leader Nigel Farage had publicly backed Mr Wilson despite the TUV and Reform UK entering an alliance for the General Election.
Sinn Féin’s Oliver McMullan received 2,986, while Margaret Anne McKilliop of the SDLP and Mark Francis Bailey from the Green Party Northern Ireland polled 892 and 568 votes respectively.
Turnout for East Antrim was 54.3%.
