There is a growing feeling that Boris Johnson is living on borrowed time.

The latest controversy over Downing Street parties places the Prime Minister at the centre of whatever took place.

Boris Johnson has used the tried and tested strategy of not saying anything about anything or about anyone as the charges are being independently investigated.

It is a classic way of dodging potentially incriminating questions and to buy some time to prepare for potentially hugely damaging conclusions.

Could he go? Well yes but equally he could continue in the role of Prime Minister if the inquiry into social gatherings absolves him.

The stakes could not be higher. The man who has coveted the job of running the country could be turfed out of office despite delivering a robust majority at the last general election just two years ago.

The simplest way would be for him to unilaterally decide to quit, should he decide that he is no longer the man for the job.

It might be seen as going before he was pushed and was how his predecessor Theresa May left the role.

While not an entirely bloodless scenario, it would be a relatively straightforward way to trigger a leadership election.

If the inquiry into social gatherings finds the PM knowingly breached the rules on social gatherings or worse attended any of the events, he could decide that his role is untenable and voluntarily call for the removal men.

Alternatively, he could be put under pressure from his own MPs and especially the ‘men in grey suits'.

That is the group known as the 1922 committee, who act as a channel of communication between the parliamentary party and the PM.

Under party rules, if enough backbench Conservative MPs write to the chairman of the committee asking for a leadership election, one must be held.

It requires at least 15% of Tory MPs to submit a no-confidence letter to make a leadership challenge possible.

On current numbers, that equates to 54 Conservative MPs needing to submit a letter to 1922 Committee chairman Sir Graham Brady.

Letters can be sent at any time and are kept confidential so no one knows who wants a vote on changing leader. However, MPs may decide to come clean and identify themselves as those who want a new leader.

The North Thanet MP Sir Roger Gale says he has already submitted a letter.

If the official investigation found that the Prime Minister either knew about the social gatherings or actually attended any that were in breach of the Covid-19 restrictions, it would heap yet more pressure on him.

If the Metropolitan Police decided to bring charges over the breach in restrictions, it is hard to see how the Prime Minister would survive.

If the outcome of a leadership vote was for Mr Johnson to gain the backing of 181 of his MPs - half, plus one - he could not be challenged for another year. Today, only three of Kent's 16 Tory MPs responded to KentOnline's approach for comment.

But he might decide that such a tight result indicated a lack of support among party activists and that would only make life more difficult for the party.

Another option would be for the PM to trigger a leadership election himself even if he wins a vote of confidence from enough MPs. This was done by John Major when he was under fire from his own MPs over Europe.

Under party rules, should more than two Tory MPs put themselves forward in a leadership contest and secure the nominations of two other colleagues, a series of secret ballots will be held to whittle them down to two.

The candidate with the fewest number of votes will be eliminated after every round until two candidates remain. As things stand, there doesn’t appear to be much interest in holding a contest and if there are candidates waiting in the wings they are keeping their powder dry for the time being.

There is also the possibility of a vote of no confidence in the government, in which all MPs could have a say.

A confidence motion may take the form of either a vote of confidence, usually put forward by the government; or a vote of no confidence, usually proposed by the opposition.

When such a motion is put to a vote in the legislature, should a vote of confidence be defeated or a vote of no confidence passed, then the incumbent government must resign, or call a general election.