She sparred with British Labour MP Yvette Cooper about the Irish border
The British Prime Minister Theresa May has repeatedly dodged calls to guarantee MPs there a binding vote on the final Brexit deal before it is formally ratified.
Mrs May faced down heated appeals on Wednesday to respect her government's defeat on an amendment to its flagship Brexit law.
She refused five times to answer a question from Labour's Yvette Cooper on if the parliament would get a vote in primary legislation on the divorce deal before EU leaders pass it themselves.
Instead she said MPs would have "had their say" on the agreement by voting through the withdrawal agreement bill.
It follows a group of Tory rebels helping pass an amendment to the Brexit Bill, giving the UK parliament the power to veto any deal reached with the EU.
Mrs May also clashed with Mrs Cooper over whether camera equipment installed on the Northern Ireland border constituted "physical infrastructure".
Mrs May said she would "not give a running commentary on every aspect as we go into negotiations on this matter", only re-stating her commitment to no hard Irish border.
"A camera is a camera - it's physical," Mrs Cooper interjected.
Mrs Cooper ended her tight questioning time at the Liaison Committee by branding the answers "baffling".
Mrs May also rubbished the SNP's Angus MacNeil claim she had gone "begging" for two more years to deliver Brexit.
As early as her Florence speech in September, Mrs May said, she had been calling for a transition period - not an extension of the negotiations with Brussels.