What next for Boris Johnson? Six scenarios that could follow the Sue Gray report

Sue Gray's report on allegations of lockdown-breaking parties in Downing Street is expected at any moment, and No 10 and Tory rebels are already planning their next steps. This is what to watch out for:

1. Boris Johnson addresses MPs

The Prime Minister has made clear he will address Parliament about Sue Gray’s findings soon after they are made public.

The position is being framed by Downing Street as a sign of how open they are being - the chance for Parliament to hold Mr Johnson accountable for what is found.

But it also has political advantages for the Prime Minister.

We do not know how much time there will be between the report being published and Mr Johnson speaking - it is in No 10’s gift - but it could be minimal.

That would allow the Prime Minister to immediately lay out his "time for change" agenda at the same time as the Gray findings are being digested by the public and MPs.

It would mean press coverage will not be just "what really happened in partygate", but also "the changes Mr Johnson has announced" - which politically is helpful for him.

2. Departures from PM’s inner circle

There is a near-universal belief among Tory MPs, government advisers and those who have Mr Johnson’s ear that an overhaul of his inner circle is coming.

The move in part reflects the Prime Minister feeling let down by his team at the scale of drinking in Downing Street, according to sources who have talked to him.

But it also comes after months of moaning from Tory MPs about the No 10 operation, both in its engagement with the Tory backbench and whether it stands up to Mr Johnson enough.

A number of senior positions which could become vacant have been much speculated upon. Plus there have been reports of senior figures offering their resignations if required.

The police investigation announcement does complicate the timing, however. Could the police probe have to run its course before sackings or resignations are announced?

3. Vows to overhaul No 10 ‘culture’

We already know that Mr Johnson will announce an overhaul of the "culture" in No 10, if Oliver Dowden, the Conservative Party chairman, is to be believed.

He toured the broadcast studios recently making that argument. The position makes sense politically, given the tricky spot Mr Johnson finds himself in.

If the public judges that the events that happened in Downing Street were unacceptable, regardless of whether laws were broken, the Prime Minister needs to promise big change.

Going by the indications from senior Tory figures, that could amount to admitting a culture of drinking on Fridays developed in No 10 and will now be eradicated.

Specifics are expected. Promising a "booze ban" has been floated in some newspapers as one option being considered.

The aim for Mr Johnson would be to convince the public and his MPs that he has accepted something wrong happened and will force through change, while remaining in post.

4. More no confidence letters

The line from scores of MPs when asked publicly and privately whether they are considering submitting letters of no confidence in Mr Johnson, is "wait for Sue Gray".

For some, this is for sure a figleaf to delay taking a public position and will be likely followed by support - senior Cabinet ministers, for example. But not all MPs.

There does appear to be a sizable chunk of Conservative MPs who genuinely are considering putting in letters if the findings are bad.

Some even claim they have already decided to but are just waiting for the report, knowing other colleagues might act then, maximising the chance of a successful coup.

The political danger is real. If 54 Tory MPs give a no confidence letter to the 1922 Committee then an up/down confidence vote in Mr Johnson is automatically triggered.

The Prime Minister's allies remain upbeat he would win that vote - a majority of Tory MPs would have to vote no confidence for him to definitely go.

But the voting is done anonymously, bringing an added layer of uncertainty as it allows supposed allies to give a thumbs' down without ever being found out.

5. A big row about Gray report material

Whenever the Gray report drops it looks like there will be an inevitable row about whether enough of the information she has gathered has been put in the public domain.

The probe’s terms of reference say she is required to deliver the "findings" of her investigation. The exact format of this has been a point of intense speculation.

Government sources have suggested the report would be a condensed version of what she found rather than a vast document with a "blow-by-blow" account of each event.

Junior civil servants are not expected to be named, in line with Cabinet Office convention used for Freedom of Information requests. Senior officials and political appointees may be.

Will it include any photographs discovered of the alleged parties? Or WhatsApp messages about their organisation? Or full witness statements of those in the room? We do not know.

Whatever form it takes, the Labour Party are sure to use every parliamentary mechanism they can to force more information into the public domain.

6. Policy reset to please Tories

The Prime Minister’s political fate rests in the hands of around 180 Tory MPs - half the parliamentary party. That is always true, but especially so during this moment of peril.

As such, there is a huge political incentive to take moves - including on policy - that gets Tory colleagues cheering and reassuring the backbench that Mr Johnson is still on their side.

So-called "Operation Red Meat" was in the works before this month's partygate revelations, but more policy announcements in that mould are expected.

Brexit is one front. The anniversary of the UK’s EU departure is next week, with a slashing of EU-era red tape expected to be announced by the Prime Minister.

Tax is another. The Prime Minister is under mounting pressure from MPs, including some in his own Cabinet, to delay April’s National Insurance rise. Could a change be coming there?

Then there is the general cost of living crunch coming at the same time, with energy bills set to soar. The Treasury is considering a range of options, including slashing green levies.

Proof that Mr Johnson at heart is not the high-tax, high-spend Tory that he has been while tackling the Covid-19 pandemic could help shore up his position, for now at least.