Sinn Fein's by-election win in Mid-Ulster has been marred by acrimony, after the victor was accused of being a suspect in the murder of the runner-up's father.
Unionist parties had joined together to put up a single candidate, Nigel Lutton, who succeeded in increasing the unionist vote to 34% in yesterday's by-election.
But he refused to shake the hand of Francis Molloy - formerly deputy Speaker in the Northern Ireland Assembly - who is alleged to have been a member of the IRA unit which shot dead Lutton's father Frederick, a police officer, in 1979.
The claim was made under protection of parliamentary privilege by Democratic Unionist party MP David Simpson. Molloy had challenged Simpson to repeat the claim outside the Commons, threatening to sue for defamation if he did so.
Despite the controversy Molloy still secured a majority of nearly 5,000, but the joint unionist tactic succeeded in cutting Sinn Fein's vote by 10,000.
The by-election was triggered by the resignation of Sinn Fein's Martin McGuinness, who stood down in line with his party's new policy of ending 'double-jobbing' to focus on his work as deputy first minister.
"I want to represent all the people of Mid Ulster, not just those who actually voted for me, not just the Sinn Fein support within the area, but all the people of Mid Ulster," Molloy told the hall after the result was confirmed.
He will not take his seat in the Commons, however. Sinn Fein MPs refuse to take the oath of allegiance to the Queen, meaning they do not actually attend debates in Westminster.
McGuinness blamed the lack of media coverage in the two-week-long campaign, fought in a mostly rural constituency, for the decline in Sinn Fein's vote.
"The media said 'Francie Molloy is home in a boat, Nigel Lutton has no prospect whatsoever of winning the election'. And I think a certain amount of complacency sets in, but for us it was a tremendous result."
Molloy won the seat with 17,462 votes. Lutton won 12,781 votes. The SDLP's candidate Patsy McGlone was third with 6,478, while the Alliance party's Eric Bullick took just 487.