LIKE most people in Britain I went to sleep on Tuesday night and woke up to a nightmare. Donald Trump: 45th President of the United States of America and successor to Abraham Lincoln, John F Kennedy and Barack Obama.

Was I still dreaming? A belligerent, semi-racist misogynist with a distant acquaintance with truth and the attention span of a gnat is President-elect and in possession of the nuclear codes. We said it couldn’t happen; not in America, the greatest democracy in the world.

But after I’d got over the shock and outrage, I began to reflect. Was this just comfortable middle-class angst? Is the liberal media getting its knickers in twist? This is democracy and the people have spoken; can it really be as bad as all that? And after a day of reflection and qualification I’d have to answer that, yes, it really is as bad as all of that. In fact, it’s probably worse.

Read more: Donald Trump's US Election victory is a 'devastating result for the world'

Mr Trump is a political leader from a work of fiction no one would believe. He is a politician who makes Francis Underwood of House of Cards look like a statesman of wisdom and intelligence. It won’t be the West Wing’s Nobel Prize-winning Jed Bartlett striding into the Situation Room and orchestrating the might of the US military but a crazy man who thinks Saudi Arabia should have nuclear weapons.

Mr Trump is a puerile fantasist who thinks he can build a 1,000-mile wall and have the Mexican government pay for it; who promises to deport 11 million mainly Hispanic immigrants; and who says he will impose 35 per cent tariffs on imports to America.

Of course, there are those celebrated checks and balances in the US constitution that are supposed to curb the excesses of executive power.

But with the US Congress – the House of Representatives and the Senate – in Republican hands and with Mr Trump about to shape the future of the US Supreme Court, which adjudicates on constitutional issues such as gun control and abortion, those checks and balances are looking rather shoogly.

Many Republican congressmen loathe Mr Trump but the Republican President has turned up a constitutional full house and potentially owns the executive, legislative and judicial branches. He may change America in ways not previously imagined.

Read more: Donald Trump's US Election victory is a 'devastating result for the world'

So what will be his first act, apart from shaking hands with the Russian President Vladimir Putin?

Mr Trump is unique in modern presidential history in having no experience of elected office, the military or international diplomacy. His grasp of economics is based on property speculation and avoiding paying tax for 20 years.

We can expect him to seek a cabinet in his image, full of cartoon military hawks, evangelical pastors, Second Amendment gun enthusiasts and other ultra conservatives. He will no doubt draft in some African Americans to show that he is not actually racist and a couple of women to show that he isn’t only interested in them sexually.

Thereafter, an encounter with economic reality will presumably lead to the early abandonment of most of his election pledges. Even if it were possible to round up the 11 million illegal immigrants he has promised to deport, the economic impact would be catastrophic, not least on agricultural “red states” that depend on their labour.

The centre-right think tank, American Action, has estimated the cost of such folly at between $400 and $600 billion.

It’s just not going to happen; ditto the “beautiful wall”.

Nor will business uphold his violation of the North Atlantic Free Trade Agreement (Nafta) and the imposition of punitive tariffs on Chinese and other imports. Most of US manufacturing takes place offshore in countries such as China, Japan and South Korea, by companies owned in America.

These are immensely powerful business interests that will ensure that Congress places limits on Mr Trump’s protectionism. The Trump solution to the economic woes of middle America – bringing jobs back home by bullying trading partners – just doesn’t work .

He will probably get through Congress his business-friendly policies such as slashing corporation tax from 30 per cent to 15 per cent and investing in roads, bridges and infrastructure.

How he will reconcile this with cutting the $19 trillion US debt pile is not entirely clear. He will also presumably get a Republican Congress to repeal Obamacare, though his low earning voters may not relish having to pay even more for their basic health care.

Read more: Donald Trump's US Election victory is a 'devastating result for the world'

The test of the Trump administration will be how he responds to these imminent setbacks.

What will be the response of those millions of Americans who voted for him when they discover that their lives are not going to get any better; that their pay – falling for 20 years – doesn’t increase; and that their country doesn’t suddenly become great again?

America is a declining superpower with immense debt, mostly owned by the Chinese, which was driven out of the Middle East after ill-conceived military adventures that cost thousands of American lives.

Where is The Donald going to seek new military success for his supporters to applaud? Iran? Syria? The South China Seas? He says he is going to leave Europe to its own devices and stop funding Nato, the foundation of America’s strategic policy for over half a century. So what is Trump foreign policy going to look like?

Like Mr Putin, he will almost certainly look for opportunities to throw his weight about. But where?

Meanwhile, Scotland has the privilege of hosting much of Mr Trump’s nuclear arsenal in the shape of Trident in the Clyde.

There is a convenient fiction that these constitute Britain’s independent nuclear deterrent but everyone knows they are America’s forward line of defence against the former Soviet Union.

If Mr Trump is serious about winding up Nato, and being friends with Russia, you might expect him to dump an obsolete weapons system that dates from the Cold War. But I wouldn’t hold my breath.

Mr Trump’s only real interest in Britain is in Brexit. He sees his movement as “Brexit plus plus plus”. Scotland figures because of his expensive golf courses and the fact that his mother was born in Lewis.

Nicola Sturgeon said he was a misogynist who should be barred from Britain because of hate speeches but I suspect we will see an early visit from The Donald if only to rub her and Alex Salmond’s noses in his victory.

The President doesn’t do magnanimous. He is a bully who likes to humiliate his rivals and he will no doubt remind the First Minister that America is Scotland’s biggest export market. These are troubled times indeed.