Her minority government means May is the weakest British leader in a generation. Yet, she must try to get her Brexit deal, struck after months of negotiations with the EU, approved by parliament before leaving the bloc on March 29, 2019.
The deal has been denounced by both supporters and opponents of Brexit.
"I'm confident this takes us significantly closer to delivering on what the British people voted for in the referendum," May told parliament. Britons voted 52-48 per cent in favour of leaving the EU in 2016.
"We will take back control of our borders, our laws and our money, leave the Common Fisheries Policy and the Common Agricultural Policy, while protecting jobs, security and the integrity of the UK."
Brexit campaigners in May's Conservative Party said her deal was a surrender to the EU, and said they would vote it down. The Northern Irish Democratic Unionist Party (DUP), which props up May's government, said it would not back any deal that treated the British province differently from the rest of the UK