THE controversy that has so dogged Boris Johnson’s three-year premiership is marking his departure. Not a surprise.

Indeed, it would be more of a shock if the blonde Beatle slipped out of Downing St quietly and with good grace.

The latest political spasm from the No 10 bunker is over the MPs’ probe into whether or not the PM lied to Parliament and the public over the Downing St parties during lockdown.

Some people believe he knew full well about the partying – indeed, he was fined for attending a “social gathering” - when he said he didn’t; Johnson maintains he had been assured all rules had been followed and so did not deliberately mislead.

However, the fact he misled MPs is clear; the nub should be whether he did so intentionally.

In what is a highly unusual move for private legal advice to Government but a clear attempt at a pre-emptive strike to get his retaliation in early, Boris appears to have sanctioned the leaking of a report he commissioned by the leading barrister, Lord Pannick, into the validity of the inquiry by the Commons Standards and Privileges Committee.

Members of Johnson’s Praetorian Guard in the media splashed the leak this morning to help create an atmosphere favourable to the PM. It’s an old Westminster tactic.

Nadine Dorries, the Culture Secretary – who else – chipped in to say: “This expert legal opinion shows that the inquiry was a biased, Kafkaesque witch-hunt; it should now be halted before it does any more damage.”

Pannick today branded the MPs’ probe “unfair” and “fundamentally flawed”.

His key point is that a failure by the committee to make an explicit distinction on the key point - whether Johnson misled MPs intentionally or unintentionally - could lead to the muzzling of other MPs, who would be terrified of misspeaking. The peer insisted this would be inherently wrong and set a damaging precedent.

Last month, the committee decided it would not have to prove Johnson’s intent to mislead MPs to show that he had committed a contempt of Parliament by obstructing its work. This decision - which cannot be challenged in the courts - was made after advice from a parliamentary official, who said intent was "not relevant" to deciding whether the PM had broken the rules.

Labour’s Chris Bryant, who chairs the committee but has recused himself from the inquiry to be replaced by his colleague Harriet Harman, noted: “The question for the committee is simple: did the PM mislead the house?

“If he misled the house, which on prima facie he did so on several occasions, is that a contempt of parliament because he didn’t correct the record swiftly enough and he was culpable?”

After the Pannick advice was published this afternoon, Bryant accused Johnson of “trying to intimidate” the committee, describing the barrister’s opinion as “bizarre” with no formal status.

“There is no danger of ministers being cowed by this inquiry – although, of course, it would be good if they were careful that what they say to Parliament is true and accurate – as the House will always recognise an honest mistake quickly corrected.”

The Welsh backbencher added: “It’s time this disgraceful bullying stopped. Let’s hear and see the evidence. If Johnson has a good case to make, he’ll be vindicated. If not, he should take his punishment.”

If the committee were to find the PM in contempt, then it raises the possibility of a suspension from the House, which could in turn trigger a by-election in Johnson’s north London seat of Uxbridge and South Ruislip.

Now a majority of 7,210 would, in normal times, be pretty safe. But, of course, these are not normal times. Labour, currently well ahead in the polls and which came second at the 2019 General Election, would in any such by-election throw the kitchen sink at trying to oust Johnson, who by then would be a former Conservative PM forced out of office by his own MPs.

Underlying all of this is the talk about Johnson wanting to make a political comeback.

Ever since his colleagues in Government forced his resignation, the PM has teasingly dropped hints here and there about how his political career might not be over just yet.

Today, the Times reported Lord Marland - a Tory peer and Johnson confidant, who led his London mayoral campaign - saying there was a “distinct possibility” the PM would try for No 10 again.

But he also pointed out Johnson’s first priority was to make money or, as he put it, “put hay in the loft,” by making speeches here and abroad; always a lucrative sideline for an ex-PM.

So, if Johnson were to harbour any hope of a Lazerene return to power, then getting thrown out of Parliament would, one might think, kill off any chance of a Johnsonian resurrection.

If it transpired the committee did find the PM guilty of a contempt of Parliament for unintentionally misleading MPs, then this would cause a stink, striking many as simply unfair.

One Number 10 insider explained: “Every day ministers go up to the dispatch box with no idea what they are going to be asked. If they make an honest mistake, it is surely wrong that they could be held in contempt of parliament.”

While, of course, voters want their ministers to be truthful at all times, however inconvenient politically it might be for the ministers, there are occasions when they say things - unintentionally -that are factually wrong.

Under Westminster rules, if this happens, then the minister concerned has to correct the record as quickly as possible.

Thangam Debbonaire, the Shadow Commons Leader, pointed out: “This current Prime Minister needs to be able to show – and the investigation’s got to be free to investigate this – that he corrected the record at the earliest possible opportunity. Otherwise, I’m afraid to say, it just looks like the sleaze and the lies and the cover-ups that people have described it as.”

Of course, the big problem for Johnson is that he is leaving Downing St because of his dishonesty, which his colleagues could no longer put up with. So, to argue on the particular point of Partygate, that it was an “honest mistake, guv,” will simply not hold water for many people.

Johnson is due to make his valedictory speech from the steps of Downing St early on Monday before he travels to Balmoral to kiss the Queen’s hand and resign. But few will believe this will be the last we hear from Boris, however much some people would intentionally wish it so.