There’s never been anything like the current open warfare between President-elect Donald Trump and the Central Intelligence Agency

Over the years, many American presidents have found themselves at odds with their spy chiefs. John F. Kennedy, Ronald Reagan and Bill Clinton are three notorious examples.

But there’s never been anything like the current open warfare between President-elect Donald Trump and the Central Intelligence Agency.

Weeks of simmering hostility exploded into the open on Wednesday when he accused intelligence chiefs of licensing the publication of false claims about his allegedly depraved sexual practices.

Trump is now engaged in a fight to the death with the CIA, the independent agency responsible for providing national security intelligence to the White House and senior U.S. policy-makers.

Only one side can win. For either the CIA will be humbled or Trump will be humiliated and destroyed.

Crucially, this isn’t just an issue that affects the United States — it is one of global importance whose outcome will affect all of us.

Also, it is a high-stakes drama which directly involves Britain, and in particular our foreign intelligence service, MI6.

We have learnt that Christopher Steele, a former MI6 officer who reportedly once headed the agency’s Russian desk at MI6 headquarters in Vauxhall Cross, South London, was the mastermind behind the dossier of lurid accusations about Trump’s activities in a Moscow hotel suite.

Whether true or not, the material suggests that the Kremlin has other documentation which it could use to blackmail Trump.

Meanwhile, the American tycoon-turned-politician is accused of being too friendly with Russian businessmen and Kremlin power-brokers.

Either way, this is an unprecedented position for an American president to be in.

Weeks of simmering hostility exploded into the open on Wednesday when he accused intelligence chiefs of licensing the publication of false claims about his allegedly depraved sexual practices

As for the Steele dossier, it was undoubtedly calculated to stop Trump being elected leader of the most powerful country in the Western world.

Being unproven, it may not be the bombshell it was intended to be. But it is still a thermo-nuclear weapon dropped into the U.S. political system. If Mr Steele were a rogue private operative, that would be troubling enough. But the evidence strongly suggests otherwise.

I have no doubt that MI6 must have had full knowledge of his role in researching and then assembling his dossier, before offering it to Trump’s political enemies.

More damning still, it has been reported that Mr Steele sought the approval of Whitehall before showing his report to the FBI, America’s domestic intelligence agency.

In other words, British spy chiefs gave the green light to a scheme intended to destroy the man who would be President of the United States of America.

Like most people, I find it very hard to comprehend this. But it is the only interpretation which makes any sense of the facts as we know them.

The Steele dossier was undoubtedly calculated to stop Trump being elected leader of the most powerful country in the Western world

If so, what on earth did MI6, a highly respected organisation, think that it was doing?

MI6 is licensed by the British government to break the law and carry out illicit acts on the assumption that it always acts in the British national interest. This is allowed under the Intelligence Services Act 1994.

But why meddle mischievously with Washington? As always, it is overwhelmingly in Britain’s interest to develop and maintain excellent relations with the American government — particularly as we negotiate Brexit.

As we leave the EU, we urgently need to strike a trade deal with the U.S., the largest economy in the world and historically our closest ally.

So why does it seem that MI6 decides to risk destroying that relationship by interfering in U.S. domestic politics? Here is what I think happened. MI6 has an exceptionally close and strong relationship with the CIA (an organisation which British intelligence officers helped to create in the immediate aftermath of World War II).

So when, as now, MI6 chiefs believe, with considerable justification, that their transatlantic counterparts are being sidelined, they feel sympathetic and want to help.

For there is little question that the CIA has two massive concerns about Trump as president.

First, it fears he is mentally unbalanced and therefore could pose a threat to American national security.

Second, the CIA is appalled at his determination to seek a rapprochement with Vladimir Putin.

For these two reasons, there are people inside the CIA who would love to see the unpredictable tycoon replaced by vice-president-elect Mike Pence, a man who they feel they can work with.

Of course, it is well-known that the CIA has an infamous record of plotting coups d’etats against democratically elected governments in other countries — for example, in the early-Fifties when it helped the Iranian military overthrow premier Mohammad Mosaddeq and reinstate the Shah, and the ousting of Chile’s president Salvador Allende in 1973.

The atmosphere is currently so feverish in Washington that there are well-informed people who now believe that the CIA is contemplating a version of the same thing in America itself.

President Trump may not last four years and Mr Pence may take over

This would be a truly appalling — and stupid — course of action. It would be incredibly foolish for MI6 even to be seen to be part of it.

Of course President Trump may not last four years and Mr Pence may take over.

If so, MI6 and its dirty tricks department will have secured the gratitude of its sister agency in the U.S.

But what if Donald Trump faces down the CIA?

Then, he will never forgive or forget the fact that Britain played such a squalid role in trying to stop him getting to the White House.

The damage to Britain’s standing in the world would be permanent, and Christopher Steele’s dossier of sexual depravity will go down as an MI6 catastrophe on the same scale as the agency’s fabricated dossier on Iraq’s supposed weapons of mass destruction.

Alex Younger, the head of MI6 and a former officer in the Scots Guards, is by all accounts a decent and sensible man. But does he know what his spy agency has unleashed? Is he in control?

One thing is certain. MI6 should never have approved Christopher Steele’s dossier on Donald Trump.

2016 was certainly a remarkable year. But the first days of 2017 have been yet more extraordinary.

We are entering times in which fact and fiction merge.

There is good reason today to feel more afraid than at any time since the Thirties.

Lord (Peter) Mandelson is believed to have made a substantial fortune out of his consultancy business, Global Counsel. But he has never declared the identity of any clients in the Lords register.

How has he got away with this?

He implausibly claims that he does not have to as his firm does not give public affairs advice.

Last week, this fiction was exploded. Mandelson hired the City grandee and former Labour minister Paul Myners.

Lord (Peter) Mandelson is believed to have made a substantial fortune out of his consultancy business, Global Counsel. But he has never declared the identity of any clients in the Lords register

As a peer, Myners has rightly added this new post to his list of appointments on the Lords Register of Interests. He describes Global Counsel, accurately, as a ‘public policy and regulatory advice organisation’ — in other words, a public affairs consultancy.

This undercuts Mandelson’s own description of the firm on the same register as a ‘strategic advice consultancy’, on which basis he has withheld the identity of its clients for over five years.

The rules are clear. If peers hand out public affairs advice, they should declare the names of their clients.

Lord Mandelson must come clean.

Dave's a fool to sup with despots

Despite his faults as prime minister, I have always believed that David Cameron was a decent man with a strong sense of rectitude and public duty.

So why is he slavishly following in the footsteps of Tony Blair?

Like Blair, he disgracefully left Parliament at the first opportunity after quitting as prime minister. Like Blair, he opportunistically set up a private firm to handle his business affairs.

And now he’s kowtowing to Middle Eastern dictators. The Middle East Eye website reveals that he’s been in the Persian Gulf to visit the crown prince of Bahrain and various business leaders.

Blair set the precedent of milking the contacts he made in office to make a fortune.

His conduct demeaned Britain, cheapened the office of prime minister and in due course caused himself to be held in public contempt.

Cameron, unlike Blair, still has a reputation to lose. I beg him — for his sake and the nation’s — to pull back from the Blairite path before it’s too late.