How long do Tories think Boris Johnson has got?

Waiting for Gray - that was the mantra of those Conservative critics of Boris Johnson's leadership, who had not quite pressed "send" on their no confidence emails.

Rather like the play Waiting for Godot, this period combined drama, farce, ennui, absurdity - and some choice language.

But it's now clear we have only reached the end of Act One, with the full Gray report still to be published, but only after the police conclude their investigations.

Again like Samuel Beckett's play, Act Two could be similar - but just more miserable.

Tory MPs can trigger a leadership contest if 54 letters of no confidence are sent to a committee of backbench MPs, known as the 1922 Committee.

They haven't passed that threshold but another Conservative politician - the MP for Waveney, Peter Aldous - said he had submitted a letter as the prime minister would not resign voluntarily.

Others are contemplating whether - or when - to follow suit.

A former cabinet minister told me: "Boris Johnson is in a very delicate position."

One waverer, the South West Devon MP Sir Gary Streeter, told BBC Radio Devon he was "wrestling with his conscience" on whether to continue to support the prime minister.

He'll decide in the next 48 hours.

I have spoken entirely off the record to other waverers, inside and outside government.

Sir Gary isn't the only one in a bout with his conscience.

Another former minister told me he was now on the verge of sending a letter: "I am asking myself how long can this go on?"

But a current minister seemed to be more representative of the mood when he said that a confidence vote could be coming, but "it is not this week. and it's not next week".

And it is probably not next month.

A former cabinet minister summed up the demeanour of those colleagues who hadn't already decided to call for Boris Johnson to go: "The mood is stable, but sullen," he said.

A serving minister suggested that there was a wider feeling of hostility towards the prime minster than he had anticipated.

But for some, Waiting for Gray has been replaced by Waiting For May - not Theresa, who has been openly critical of her successor, but the date of the forthcoming council elections.

So far, with the exception of one parliamentary aide - Angela Richardson - ministers and the so-called payroll vote publicly have stood firm.

But privately, some junior ministers have been discussing the prime minister's future.

And the consensus emerging from what are very informal discussions is that any likely move against Mr Johnson would follow in the wake of those local elections.

This is in part due to what has been seen as a disconnect in some parts of the country between the view of some constituency association activists - who are incredulous that MPs could consider ditching an election-wining prime minister for attending a party - and Conservative voters, who have been angered by the 'partygate' reports and the allegations of rule-breaking.

So if the May elections suggest there is a serious political consequence to the events in Downing Street, and Conservative ex-councillors kick up, more MPs will be emboldened to call for a confidence vote.

One minister said that Boris Johnson had, in effect, three months to sort out No10 and turn the polls round.

One very astute observer of the political landscape suggested that what would most concern colleagues is if the May election results started to show slippage to the Lib Dems in some areas and to Labour in others - a pincer that could put under threat an apparently large majority at Westminster in due course.

There was also fear that the integrity (or lack of it) question might influence volatile voters and taint the image of party and not just the prime minister.

Several MPs told me that while they too subscribe to the "wait until May" analysis, with 300 photographs in the hands of Sue Gray and the Met, the prime minister could be destabilised sooner if any damaging images get into the public domain.

As one of them put it bluntly, "what kind of idiot photographs themselves at what they probably knew to be a rule breaking event?"

Another said the pledge to allow Gray to update her report and to publish it in full had to be "dragged kicking and screaming" from the PM, and now that report - whenever it appears - could finish him.

And a former Cabinet minister said he expected it to be a "humdinger of hostility".

Others believe Boris Johnson could yet weather the storm.

A senior backbencher suggested 'partygate' had been simply a spectacular symptom of a badly-run Number 10, and if this could be reformed convincingly then the prime minister's tenure could be more secure. But promises of reform would not be enough - he would want to see results.

An ex-minister wanted to see personnel changes at Cabinet level and not just in the backroom operation, and a former Cabinet minister, who is privately critical of Boris Johnson, believes the prime minister has a breathing space.

His view is that "Downing Street is a mess - the failure of leadership (identified by Sue Gray) is his, and the civil servants" but while "those who hate him continue to do so...there's no mood amongst colleagues more widely to move against him right now".

He felt the expanded and potentially gory sequel to the Gray report may be some way off, and the public were already showing signs of wanting to move on.

But that could represent a move out of the frying pan and into the fire.

He said: "Look where he is moving on to - the cost of living. The May elections will be very important to colleagues. He is not out of the woods yet."

A former Cabinet colleague agreed that this was the "central forecast" from the backbenches.

But another factor may yet sustain Boris Johnson.

While he may still be in the woods, some of his colleagues perhaps don't yet see the wood for the trees.

There is no unity behind one single candidate to replace him, or agreement on exactly what might trigger a further flurry of no confidence letters - never mind a sufficiently co-ordinated campaign of letter writing (though that may come).

But the lack of unity wouldn't necessarily help Mr Johnson, according to one ex-cabinet minister.

"The trouble is if he tries to move one way to appease some colleagues, [no confidence] letters could go in from others. If he moves in the opposite direction, then he will just provoke a different set of letters."

On the record, talking to BBC Radio Stoke, the Newcastle-under-Lyme MP Aaron Bell - who has been critical - suggested that amongst other colleagues elected for the first time in 2019 "there is a very lively discussion about what the right thing to do is".

One former cabinet minister felt that David Davis and Andrew Mitchell had jumped too soon in publicly withdrawing support and would have little influence with the '2019ers'

But another former Cabinet minister gave me this assessment: "This is now death by a thousand cuts.

"Of course more stuff will come out, then we'll have the locals. It all goes on for now, but we all know this is not going to end well."