US President Donald Trump has become the first world leader to congratulate Boris Johnson on his election win.
Mr Trump said it would pave the way for a "massive new trade deal" after Brexit.
During the campaign Labour repeatedly warned that the US would want to get its hands on the NHS, and the nightmare before Christmas opens the door for these talks to open.
The US President wrote on Twitter : "Congratulations to Boris Johnson on his great WIN! Britain and the United States will now be free to strike a massive new Trade Deal after BREXIT. This deal has the potential to be far bigger and more lucrative than any deal that could be made with the E.U. Celebrate Boris!"
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Johnson said: said: "We must understand now what an earthquake we have created. The way in which we have changed the political map in this country.
"We have to grapple with the consequences of that. We have to change our own party.
"We have to rise to the level of events. We have to rise to the challenge that the British people have given us."
The Prime Minister's victory puts Britain firmly on course to leave the EU next month, and he will seek to strike a free trade deal by the end of 2020.
Jeremy Corbyn said he would not lead Labour into another election campaign.
But he said he would stay on to oversee a period of "reflection" - and the selection of a new leader.
Big Labour names including Keir Starmer, Emily Thornberry, Becky Long-Bailey, Angela Rayner and Laura Pidcock are all expected to throw their names in the ring to replace Corbyn.
The SNP appeared to have wiped out other parties in Scotland which would boost calls for independence.
Shadow International Trade Secretary Barry Gardiner said: “It is a deeply depressing prediction.
“Really my heart goes out to all the people who had given their hope to the Labour Party, who really were relying on us to be able to improve their lives.”
And Shadow Home Secretary Diane Abbott wrote: "This is clearly a bad night for Labour, which requires careful analysis. But it could be much worse than a bad night for all those who rely on our public services and the NHS. Which means we still need leadership that fights for the many, not the few."