Big Brexit day: Here's what will happen in UK parliament on Tuesday

If May loses the vote, she is required by parliament to come back within three working days with a motion setting out her next steps

Prime Minister Theresa May must win a vote in parliament to get her Brexit deal approved, or risk seeing Britain's exit from the European Union descend into chaos.
 

May postponed a parliamentary vote on her deal last month, admitting she was set to lose it, and pledging to seek assurances from the EU to help win over lawmakers. The vote is now due to take place on January 15
 

To win, May and her ministers have to overcome opposition from across the political spectrum.
 

Here's how the voting will work:
 

WHO?
 

The debate takes place in the lower house of