The Clare TD Michael McNamara has voted against the Government on the abortion legislation in what the Labour Party is saying was a "mistake".
The Dáil will continue debating the abortion legislation later today after failing to finalise the Bill at 5 o'clock this morning.
While European Affairs Minister Lucinda Crfeighton remains in her job, she's still expected to revolt and vote against the legislation.
After approaching 12 hours of debate in the Dáil chamber TDs had only reached the fifth group of amendments, with many more to go.
Although amendments dealing with the suicide clause were debated, many had not been voted on - including those from Minister Lucinda Creighton.
So far she has voted with the Government, but is expected to vote against either on her own amendments or on the final stage vote.
But in a surprise move at ten to five this morning the Clare TD Michael mcNamara in the dying seconds of a vote on fatal foetal abnormalities cast a vote against the Government.
Michael McNamara TD, LAB, pictured at a party event at the 2011 election
Colleagues immediately questioned him and the Labour Whip is adamant that eventhough the vote cannot now be changed, no further action will be taken against the deputy.
While the Government is reluctant to impose a guillotine, already the legislation is now behind schedule, due to have started its passage in the Seanad this afternoon.
But instead the Dáil will sit from 4pm this evening, with all stages due to have completed there by midnight.
Newstalk's Political correspondent stayed with the debate through the night: