Downing Street says Dominic Cummings still under investigation over ‘chatty rat’ leak

Cummings has 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.

In an incendiary blog post, Cummings went on to say that Case had told Johnson that neither he nor the then No 10 director of communications Lee Cain was the culprit.

However officials familiar with the investigation said that it had neither “landed” on any one individual or exonerated anyone.

The disclosure is likely to further anger Cummings who released his onslaught after he was accused by No 10 of a series of damaging leaks including text message exchanges between Johnson and the entrepreneur Sir James Dyson.

Ministers are now concerned at what he may say when he gives evidence to MPs investigating the government’s response to the pandemic next month.

Cummings is widely known to have been critical of Johnson’s delay in launching a second lockdown in England when cases began rising last autumn and there is speculation he will seek to blame him for the high death toll.

The Daily Mail carried a claim that following the lockdown the prime minister had said he would rather see “bodies pile high in their thousands” than order a third one.

The paper did not give a source for the allegation which it said Downing Street had dismissed as “just another lie”, but the report will only add to the febrile mood at Westminster.

Meanwhile Labour will focus on another of Cummings’ allegations as it attempts to force ministers to explain how Boris Johnson paid for the lavish refurbishment of his official Downing Street flat.

The opposition will ask Commons Speaker Sir Lindsay Hoyle to grant an urgent question requiring a minister to come to the House to respond to the charge that Johnson plotted for Tory donors to secretly fund the work.

Over the weekend, the International Trade Secretary Liz Truss insisted Johnson had complied fully with the rules and had paid for the refurbishment, which reportedly ran to £200,000, out of his own pocket.

But during a round of broadcast interviews, she repeatedly refused to say whether the bill was initially settled by the Conservative Party, or one of its donors, in which case it should have been declared as a loan under party funding rules.

Labour deputy leader Angela Rayner said there was a “real stench” around the government and she called for the Electoral Commission, which polices the party funding rules, to launch a full inquiry.

The commission, which first raised the issue with the Conservative Party more than a month ago, confirmed at the weekend it was still looking into whether any of the sums relating to the work on the flat should have been declared.

Last week, the Daily Mail published details of an email from Tory peer Lord Brownlow in which he said he was making a £58,000 donation to the party “to cover the payments the party has already made on behalf of the soon-to-be-formed ‘Downing Street Trust’”.

To date, no such trust has been formed.

Case, meanwhile, is likely to face questions during his appearance before the PACAC, about another issue where Labour is hoping to make ground, what it describes as Tory “sleaze”, David Cameron’s lobbying on behalf of Greensill Capital.

MPs are expected to press him on the extent of the former prime minister’s activities on behalf of the failed finance company following the disclosure he used his contacts to directly approach chancellor Rishi Sunak, health secretary Matt Hancock and the deputy governor of the Bank of England.

Earlier this month Case ordered all senior civil servants to declare whether they had outside jobs after it emerged that the former head of government procurement had taken a position with Greensill while still working in Whitehall.