The Supreme Court this morning ruled Mrs May will have to first seek the consent of MPs and peers before triggering Article 50 to begin EU exit negotiations.
Following the judgement, Brexit Secretary David Davis informed the House of Commons the Government will be tabling legislation to authorise Article 50 "within days".
In exchanges following Mr Davis's announcement, Labour's shadow Brexit secretary Sir Keir Starmer blasted the Government's Supreme Court appeal as a "waste of time and money" as he told the Prime Minister she was "wrong to have attempted to sideline Parliament" in the Article 50 process.
In last month's Supreme Court hearing the Government had argued 'royal prerogative' powers should have given Mrs May the right to invoke Article 50 alone and without having to hold a parliamentary vote.
Theresa May mouthed the word 'referendum' to mocking Labour MPs as David Davis spoke
David Davis told MPs the Prime Minister had not been aiming to 'sideline democracy'
In a retort to Sir Keir's accusation this afternoon, Mr Davis told MPs the Prime Minister had not been aiming to "sideline democracy" with the Government's appeal to the High Court.
And, as her Brexit Secretary spoke, Mrs May mouthed the word "referendum" to the mocking Labour benches.
Following an intervention from House of Commons' Speaker John Bercow in a bid to halt MPs' barracking, Mr Davis added the Prime Minister was merely attempting to "carry out the will of the people, 17.4million of them, in the national interest".
Last week it was reported up to 80 Labour MPs could vote against Article 50 legislation in defiance of the EU referendum result.