You have woken up this morning in a new country. It is a country divided as never before, with two major political parties facing existential crises after a brutal election night.
I am writing at dawn on Friday morning, in the expectation that by the time you read these words, one party leader, Nick Clegg, will be preparing his resignation statement, and another, Ed Miliband, likely to be standing down very soon.
It is a measure, though, of the magnitude of the overnight political earthquake that the futures of the Liberal Democrats and of the Labour party are not the main story today. It is perfectly possible that when you cast your vote yesterday, it was in the last election to be held in the UK in its current form.
The most urgent task facing David Cameron this weekend, having won an unexpectedly comfortable number of seats in the Commons, is to come up with something to re-engage Westminster with the people of Scotland. They may have voted against independence last September; yesterday the pro-independence SNP pretty much swept the board and consigned Labour in Scotland to a pitiful irrelevance.
The first UK election I reported on was in 1979, when Margaret Thatcher swept into Downing Street. It felt like a moment of history; we knew she would change the country. But yesterday's election was of an entirely different order: because of the rise of the SNP, and of UKIP in many different parts of England, the future of the UK is now in question as never before.
For the Liberal Democrats, the results weren't as bad as they had feared - they were much, much worse. Having volunteered their support to the Conservatives five years ago in a coalition, they have now been squeezed to within an inch of their lives. It will take them many years to recover from the beating they received yesterday.
For Labour, a long, deep, painful rethink is called for. At the time of writing, they have lost as many seats to the Tories as they have won from them - that is a truly appalling result after five years of Tory-imposed austerity and its impact on people's living standards. The inquest will have to go beyond the usual "What went wrong?" that follows any defeat - it starts with "Who are we?" and "What do we stand for?" and then moves on to "How do we regain the trust of the British people?"
Ed Miliband thought he had created a coherent political philosophy that would appeal to large numbers of British voters. He was wrong. He was unable to meet the threat of the SNP north of the border, just as he was unable to stop UKIP eating away in Labour heartlands south of the border. It will be no easy task to develop a strategy that meets both those challenges.
David Cameron is about to be severely tested. He flunked his response to the Scottish independence referendum last year by appearing to care more about the future of England than he did about Scotland. In the small hours of this morning, he spoke again about "one nation and one United Kingdom" and about governing for all the people. We shall see - Boris Johnson, now back in the Commons and snapping at his heels, has already suggested that the Tories will have to make "some kind of federal offer" to the people of Scotland to meet at least some of their aspirations. It is going to be a difficult and uncomfortable period.
And then, of course, there's the EU. Mr Cameron has pledged a renegotiation of the UK's terms of membership followed by an in-out referendum. It is not entirely fanciful to imagine that by the time of the next election, Scotland will have split away from the UK, and the UK, or what remains of it, will have left the European Union.
Today, the Tories may feel as if they have won a wonderful victory. The truth is that they are in for a very difficult time. They have few allies in the new House of Commons and the massed phalanx of their opponents will be ready to exploit every opportunity to trip them up or stop them in their tracks.
My guess is that many people will soon be recalling almost with fondness the relative stability of the Tory-Lib Dem coalition. Labour, presumably under a new leader, and the SNP, heralded by Alex Salmond as the Scottish lion that roared, will be in no mood to accommodate the Tories' plans for more public spending cuts and a continued squeeze on welfare programmes. Mr Cameron may wish to consult John Major on the joys of governing on a knife-edge.
Be grateful, though, at least for this: there will be no constitutional crisis, no weeks of haggling to cobble together a new coalition. The Tories won. Just.