It comes amid reports there are plans to save the Prime Minister by blaming staff in a move named “Operation Big Dog”.
Martin Reynolds, Mr Johnson’s principal private secretary, is said to be facing the chop after he sent the email inviting more than 100 staff to the “bring your own booze” event in No. 10’s garden on May 20 2020.
But when the Prime Minister’s official spokesman was asked whether Mr Johnson was referred to by staff as “big dog”, he said: “I’ve never heard that term used.”
Asked whether Mr Johnson referred to himself by the nickname, the spokesman said: “Certainly not that I am aware of.”
At a briefing with journalists, Downing Street also dodged questions over Mr Johnson’s commuting between Chequers and No. 10 during March 2020 while his wife was pregnant.
The Prime Minister’s official spokesman was asked about reports by news website Tortoise that alleged Mr Johnson had commuted between his country residence and No. 10 between March 16 and 27, 2020, when guidance said people should not travel for non-essential reasons.
He said: “At the time, as you know, Mrs Johnson was heavily pregnant and had been placed in a vulnerable category and advised to minimise social contacts, so in line with clinical guidance and to minimise the risk to her they were based at Chequers during that period, with the Prime Minister commuting to Downing Street to work.”
The spokesman said there would have been staff at Chequers with the couple.
He said the guidance on not travelling to second homes did not come in until March 22, 2020 “at which point the Prime Minister and his wife were already based in Chequers, acting in line with clinical guidance”.
Asked if the PM was therefore putting his wife at risk by commuting during the period, the spokesman said: “The Prime Minister was leading the coronavirus response, the pandemic response, and in line with a number of individuals who were required to still be in work … that’s why the Prime Minister was coming to No. 10 for necessary work meetings.”