The Supreme Court will announce next Tuesday if Theresa May must get the consent of MPs and peers before she starts Brexit.

The eagerly-awaited ruling – on whether the Prime Minister has the power to bypass Parliament before triggering the Article 50 exit clause – will come at 9.30am.

If, as expected, the Government loses, a Bill is likely to be rushed through Parliament within days to comply with the judgement.

Ms May has insisted a defeat will not derail her timetable to invoke Article 50 by the end of March – kick-starting a two-year exit process.

However, the need for legislation could give pro-EU MPs and peers the opportunity to table amendments, to try to influence the Government’s course.

The Liberal Democrats have vowed they will attempt to force through a second referendum on the final Brexit deal, but lack Labour support.

More troublesome for Ms May would be a ruling that she must seek the consent of the devolved administrations in Edinburgh, Belfast and Cardiff before moving ahead.

The question of Northern Ireland is particularly contentious – after the Supreme Court heard evidence that Stormont is responsible for some border issues.

The need for full consent would plunge the United Kingdom into a full-blown constitutional crisis, as well as potentially sink the Prime Minister’s exit timetable completely.

In addition, the Supreme Court may also make a ruling on whether Article 50 – and, therefore, Brexit itself – could later be stopped, if Parliament chose to.

The Government is believed to have already drawn up at least two versions of a Bill that could be tabled to comply with an anticipated defeat.

It has been suggested that the Government expects to lose by seven votes to four, when the 11 Supreme Court judges rule on Article 50.