A judicial challenge has been launched after Sinn Féin took the Fermanagh and South Tyrone Westminster seat by four votes, a courts spokeswoman confirmed today.
Michelle Gildernew was declared the winner after the third recount.
Unionist unity candidate Rodney Connor asked for the Belfast Election Court review after this month’s narrow defeat.
A spokeswoman for the Lord Chief Justice’s Office said: “We have had an application lodged by Rodney Conner.”
The third recount in the largely rural area started at 11am the following day after the overnight race between the two candidates was judged too close to call.
After the first count, only eight votes separated the independent unionist candidate and the Sinn Féin minister, sparking a re-count at 3am.
After three recounts, the first giving Mrs Gildernew the edge by 10 votes, then two and finally four, the tightest of contests was declared for Sinn Fein.
The Fermanagh and South Tyrone seat was won by IRA prisoner Bobby Sands in 1981 when he was on hunger strike.
Since then, it changed hands between nationalism and unionism until Ms Gildernew won in 2001.
She was elected by just 53 votes, resulting in legal challenges after complaints about polling stations staying open too late.
The smallest majority ever recorded by a candidate was in Exeter in 1910 when one vote decided the winner.
There was also a tie for the seat in Ashton under Lyne in 1886.