Boris Johnson: What could happen after Partygate hearing?

The former prime minister is facing a panel of MPs who are investigating accusations that he did not tell the truth to Parliament over Partygate.

Boris Johnson will be questioned by the Privileges Committee on Wednesday, about statements he made over Covid rule-breaking parties in Downing Street.

It is a significant moment for a political system, such as the UK's, that largely relies on trust to function.

It could also be a big moment for Boris Johnson personally and could cause some serious political fallout.

This is possible, although it does not, at this stage, seem the most likely outcome.

That is because the committee has already published a report, after gathering evidence, which identifies one statement he made which later turned out to be wrong.

The report also identifies three other ways in which they say Mr Johnson may have misled Parliament.

It says their evidence suggests it "would have been obvious" to him that Covid guidance had been broken in Downing Street at the time that he told MPs it had not.

The committee was also clear, though, that its conclusions were not yet final.

It is possible that Mr Johnson gives explanations in the hearing that satisfy the committee.

It could also decide that Mr Johnson did mislead Parliament but that it did not make any difference to how it functions and therefore it was not a "contempt".

In these cases, Mr Johnson would not face any sanction.

The committee could also decide that any contempt was "inadvertent" - which would be less likely to lead to a sanction.

Mr Johnson is arguing that what he told the Commons was his "honest belief".

At the other end of the scale is the very worst case scenario for Mr Johnson.

Getting to this situation would take a LOT of stages.

Firstly, the committee would have to decide that Mr Johnson had not only misled Parliament but also that what he said had an impact on its "proper functioning". This would mean it was a "contempt".

They would also have to conclude that the contempt was so severe that they decide to recommend one of the most severe punishments available to them: suspension from Parliament for 10 sitting days or more.

That would trigger a recall petition. If 10% of eligible registered voters in his Uxbridge and South Ruislip signed the petition, his seat would be declared vacant and a by-election would be called.

An MP who is kicked out through this process is allowed to stand in any subsequent by-election to try to win the seat back.

There are a lot of "ifs" in this process though and it is unlikely to be something the Committee would do lightly.

Any punishment would have to be agreed by a vote of the whole House of Commons - and a sanction that endangers Mr Johnson's political future is likely to prove very controversial.

The committee does also have the power to recommend expulsion - kicking an MP out of Parliament without asking the local electorate. But that is very rarely used.

If the committee does find Mr Johnson was in contempt of Parliament they will take a view on how serious it was.

They will take into account what the impact was and whether they think Mr Johnson had done it inadvertently, recklessly or deliberately.

That will help them decide if he should face a sanction and what it should be.

Punishments could range from: asking him to make a written apology, making him apologise in person in the Commons, up to suspension.

Whatever the outcome, the hearing risks bringing tensions within the Conservative Party back to the surface.

Some of Mr Johnson's supporters already believe that launching the investigation was politically motivated so expect some backlash, whatever is decided.

It is also likely to raise fresh questions about how Parliament polices itself.