MP for Peterborough Lisa Forbes helped defeat the Government on an amendment which could thwart efforts by the next Prime Minister to force through a no deal Brexit.
The Commons backed the move by 315 votes to 274 which could stop the next PM suspending Parliament in order to allow the UK to crash out of the EU.
Earlier this month Labour MP Ms Forbes, who was elected in June, told the Peterborough Telegraph a no deal Brexit would be “catastrophic” and that she would not vote for it.
She said: “I campaigned and said I would support a deal that protects jobs, protects people’s living standards, protects the environment and consumer protections and workers’ rights as well. I’ve not moved from that position.”
North West Cambridgeshire MP Shailesh Vara, North East Cambridgeshire MP (and Brexit Secretary) Steve Barclay and Corby MP Tom Pursglove all voted against the amendment.
Grantham and Stamford MP Nick Boles and Huntingdon MP Jonathan Djanogly voted in favour of it.
South Holland and the Deepings MP John Hayes did not vote.
The vote came after the Lords strongly backed a bid to block Parliament being suspended in order to facilitate a no deal exit by a margin of 103 votes on Wednesday.
The change to the Northern Ireland (Executive Formation) Bill will require progress reports on restoring devolved government in Northern Ireland to be debated regularly in Parliament, effectively preventing it being prorogued.
Front-runner for the Tory leadership Boris Johnson again refused at the final campaign hustings on Wednesday to rule out proroguing Parliament in order to meet his red line of getting the UK out of the EU by October 31.
His rival for Number 10 Jeremy Hunt has insisted he would not use such a constitutional manoeuvre.
The amendment to the Northern Ireland (Executive Formation) Bill builds on an amendment passed in the Commons last week, when MPs backed a proposal from the pro-European Tory Dominic Grieve calling for fortnightly reports from the Government on the efforts to restore the powersharing executive.
The new Lords amendment would ensure these have to be debated in the weeks before the Brexit deadline.
The bill could theoretically make it illegal for the Government to prorogue Parliament in the autumn if the powersharing executive in Northern Ireland has not been restored.