Boris Johnson will submit a “bombshell defence dossier” of evidence to MPs as he attempts to clear his name over allegations he misled Parliament over the Partygate scandal.
The former prime minister will provide the statement to the Privileges Committee as he battles to save his political career.
Mr Johnson will appear before the panel on Wednesday for a televised grilling, and it is expected he will submit his written evidence before then.
In an interim report, the Privileges Committee said the evidence strongly suggests breaches of coronavirus rules in No 10 should have been “obvious” to Mr Johnson.
They are examining evidence around at least four occasions when he may have deliberately misled MPs with his assurances to the Commons that rules were followed.
Allies of Mr Johnson said he would provide a “detailed and compelling” account to the committee before his appearance, showing that he “did not knowingly mislead the House”.
The Sunday Times reported he will point to a series of previously undisclosed WhatsApp messages from senior civil servants and members of his No 10 team showing that he had relied upon their advice when he made his statements to Parliament.
He will also publish messages which show that other senior figures in Downing Street believed the gatherings were covered by the “workplace exemption” in the lockdown rules.
And The Telegraph reported that his “bombshell defence dossier” will contain “new evidence that helps his case”.
“His case is that he told Parliament what he believed to be true at the time. There is documentary evidence which will show that he was advised to say what he went on and said,” the newspaper reports.
The committee’s investigation is being chaired by Labour’s Harriet Harman, although the seven-strong panel has a Tory majority.
The committee will publish its findings on whether Mr Johnson committed contempt of Parliament and would make a recommendation on any punishment, but the ultimate decision would fall to the full House of Commons.
Prime minister Rishi Sunak has said he would not seek to influence MPs on the committee and indicated he would grant a free vote to Conservative MPs on any sanction that may be recommended.
Asked if he was not concerned that a suspension of more than 10 days could trigger a by-election in Mr Johnson’s Uxbridge and South Ruislip seat, Mr Sunak added: “This is a matter for Parliament, for the House. It’s not right for the government to get involved.”