Boris Johnson did not try to block the investigation into who leaked the decision to impose the second lockdown, the top civil servant has suggested, as he said a culprit is yet to be identified.
Simon Case declined to comment on Monday on whether the prime minister’s former chief aide Dominic Cummings had been cleared of being the so-called “chatty rat” who tipped off the press.
But the cabinet secretary said the prime minister did not try to block the investigation, after the Vote Leave veteran alleged he had considered the move.
Case told the Commons Public Administration and Constitutional Affairs Committee that the leak inquiry is “ongoing” in a “clear indication that the source or sources haven’t been identified”.
He said it is “probable that the team will not successfully identify the source or sources” given the time that has passed and estimated it will be concluded within “weeks rather than months”.
His appearance before MPs comes after an incendiary blog post from Cummings, which was triggered by Downing Street sources telling newspapers he was suspected of having leaked the prime minister’s correspondence.
Cummings, who left Downing Street last year amid a bitter power struggle, accused Johnson of seeking to block the investigation after learning that a close friend of his fiancee Carrie Symonds had been implicated – a claim the prime minister denied.
The controversial former adviser went on to say that Case had told Johnson that neither he nor the then No 10 director of communications, Lee Cain, leaked the decision to impose a second coronavirus lockdown in October.
Citing the “security classification” of the leak inquiry, Case said he was “very constrained in what I can say”.
He was asked if he had authorised Downing Street to tell the media that neither Mr Cummings nor Mr Cain were the leakers, as Cummings claimed.
“I am not trying to frustrate, but this is drawing me into details of an ongoing investigation which – for reasons I have set out – I can’t go into in this setting,” Case told MPs.
Asked by chair William Wragg if an outcome had been “actually desired”, Case said that “from the outset” the prime minister and others were “determined” to find the culprit.
Pressed if he knew of an investigation being stopped because the outcome would be embarrassing, Case said: “No, in relation to this particular leak and others, the prime minister has always been clear, very determined to see these inquiries complete.”
Case said a process involving the police and Crown Prosecution Service concluded “this leak did not meet the threshold for an offence under the Official Secrets Act or the offence of misconduct in public office”.
He said there is a “long-standing policy of neither confirming nor denying” whether the security services had been involved in the leak investigation.