IS the United States of America about to experience its own Brexit moment?

Tomorrow millions of people will vote for a new President. The choice essentially comes down to Hillary Clinton or Donald Trump.

After the most bitter, divisive and dishonourable campaign in history most opinion polls show Clinton with a slight edge. But the polls have been wrong before – remember how many of them predicted a narrow majority in favour of staying in the European Union – and the difference between Clinton and Trump is well within the margin of error.

We know Donald Trump will have no trouble turning out his voters. Support at Trump rallies borders on the fanatical.

But support for Clinton is lukewarm, even among Democrats.

Around a third of ballots – at least 41 million – have already been cast in early voting and there have been worrying signs that Clinton’s support is going soft.

So what happens if voters put Donald Trump into the White House?

We have already seen market jitters on the possibility of a Trump victory and dire predictions of a slump in the dollar if that comes to pass. It all looks a lot like pre-Brexit Britain in the days before June 23.

Three months ago we said Donald Trump was not fit to be the Leader of the Free World.

Nothing he has done, or said, since has made us change our minds.

But if Trump is the winner this week, Britain, and the rest of the world, must find a way to work with him.

That won’t be easy for allies and enemies alike, but we are confident the UK’s diplomatic service will find a way.

The Special Relationship between Britain and the United States is bigger, and more important, than any individual.