They are worried that if she hands her report to No 10 on Friday – when Parliament is all but deserted as MPs visit their constituencies – the PM could delay publication to Monday while allies use the intervening time to plant stories in the weekend press putting the best possible gloss on its contents.
One rebel told The Independent: “If they have it in their hands for three days before Boris has to make his statement to the house, there’s no doubt it’ll leak like a sieve and there’ll be an effort to control the narrative and suggest he’s in the clear.”
There is concern among Johnson’s Tory critics that the long drawn-out process of producing the report may be dissipating momentum behind the drive for the 54 letters needed to trigger a confidence vote in his leadership.
The PM was away from Westminster on a visit to north Wales on Thursday, forcing a break in the charm offensive which has seen him talking with dozens of wavering MPs in his bid to stave off revolt.
His shadow whipping operation continued in his absence, and allies Christopher Pincher and Conor Burns have set up a WhatsApp group for loyalist MPs to discuss their support for the PM.
This may have backfired, however, with one backbencher revealing that he knew of four participants who had sent the group messages of unswerving fidelity, despite having already submitted confidence letters to 1922 Committee chair Sir Graham Brady.
His meetings with MPs have not always paid off either. One former minister told The Independent: “I’m not the letter-writing type but he invited me in for a chat and I went to see him and told him what I thought. I don’t think he was very happy about it.”
In what is widely seen as an effort to scare red wall MPs in marginal seats away from a confidence vote, a second cabinet minister warned that the UK would be forced into a general election if Mr Johnson was ousted.
Culture secretary Nadine Dorries said that the emergence of social media and 24-hour news meant politics was in “very different times” to 2007, when Tony Blair handed over to Gordon Brown without an election.
Her comments echoed Commons leader Jacob Rees-Mogg, who said the UK now had “essentially a presidential system”, so any new PM would need their own mandate from the electorate.
Ms Gray’s report into potentially lockdown-busting events in Downing Street and Whitehall departments was due for publication this week after being repeatedly delayed as new allegations emerged. From an initial inquiry into a single Christmas party, it is now expected to cover as many as 15 different gatherings over 2020 and 2021.
But its release was knocked off track by Tuesday’s announcement of a separate police investigation, covering an unknown number of these events.
Civil service investigators were locked late into Thursday evening in discussions with the Metropolitan Police over how much of Ms Gray’s report – believed to make uncomfortable reading for the prime minister – can be released without compromising the criminal probe.
Sources close to the Gray team were unable to estimate when the report may finally be signed off and handed to the prime minister.
But they made clear that delivery to No 10 would not be delayed to fit in with the parliamentary timetable, in which Monday is the earliest likely date for the oral statement and debate which Mr Johnson has promised.
Ms Gray’s main consideration is to complete the report to her satisfaction and then present it to the PM, and the question of whether the timing is favourable or not to No 10 will not be taken into account.
The office of Commons speaker Sir Lindsay Hoyle has made clear that, if requested by No 10, he can schedule a prime ministerial statement for Friday, when the agenda is currently occupied by poorly-attended debates on backbench MPs’ bills.
A senior minister told The Independent that MPs would be expected to rush back from their constituencies, as they have in the past for hastily-called emergency statements. But rebels fear that if the report goes to No 10 late on Friday, it may not be published until Monday morning, a matter of hours before the PM’s statement.
Downing Street has committed to publishing “as soon as possible” after the report is received, and Mr Johnson said that “of course” it will be released in full.
But No 10 sources stress that they do not yet know the format or content of the report and, while the intention is to publish it in exactly the form it arrives from Ms Gray, some time will be needed to assess whether this is possible.
They cited concerns that junior staff should not be identified and personal information such as addresses should be protected, as well as the need to be assured by Scotland Yard that its contents do not cut across police inquiries.
Labour leader Sir Keir Starmer said it would be “unthinkable” for the report not to be published “in full and as soon as possible… Not redacted, not edited, not a summary, not parts left out. In full.”
Speaking during a visit to Grimsby, Sir Keir said: “After what everybody in the country’s been through in the last year or two with the pandemic, huge sacrifices have been made, the least that they’re entitled to is the truth about what the prime minister was up to.”
Mr Johnson’s official spokesperson dismissed suggestions that the PM and his government had been distracted from policymaking by the Partygate saga, telling reporters: “No, we are getting on with the job, as the prime minister said yesterday.”
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