In an emotional statement at Downing Street, she said she had “done my best” to honour the 2016 European Union referendum result. She added that it would always be a “matter of regret” that she had been unable to deliver Brexit, and said whoever will be her successor will need to build a consensus in government.
"Such a consensus can only be reached if those on all sides of the debate are willing to compromise," she said.
On 25 April 2016, one month before the referendum, May was a staunch Remainer and delivered an impassioned speech about why Britain should remain in the EU.
Here is what she said.
(You can watch the video below)
I think we should stay inside the EU. Remaining inside the European Union does make us more secure. It does make us more prosperous and it does make us more influential beyond our shores.
It is clearly in our national interest to remain a member of the European Union. I think it’s right for us to remain precisely because I believe in Britain’s strength. In our economic, diplomatic and military clout.
On the economy
Because I am optimistic about our future. Because I believe in our ability to lead and not just follow. Given that British exports in goods and services to countries outside the EU are rising one can hardly argue the EU prevents this from happening.
Leaving the EU on the other hand, might make it considerably harder.
It’s not realistic to think we could just replace European trade with [other] markets.
And the reality is that we do not know on what terms we would have access to the single market. We do know that in a negotiation we would need to make concessions in order to access it, and those concessions could well be about accepting EU regulations, over which we would have no say, making financial contributions just as we do now, accepting free movement rule. Just as we do now, or quite possibly all three combined.
Remaining a member of the European Union means we will be more secure from crime and terrorism.
Free movement rules mean it is harder to control the volume of European immigration but they do not mean we cannot control the border.
The fact that we are not part of Schengen – the group of countries without border checks – means we have avoided the worst of the migration crisis that has hit continental Europe over the last year.
Brexit also risks changing our friendships and alliances from further afield. Britain can, and often does lead in Europe.
Of course Britain could cope outside the European Union. But the question is not whether we could survive without the EU but whether we are better off, in or out.
She concluded: “The case to remain in the European Union remains strong.”