Sajid Javid, the health secretary, pulled out of Wednesday morning's broadcast interviews after a video emerged showing No 10 aides laughing about a Christmas party during Covid restrictions.
Javid was due to appear for the one-year anniversary of the vaccine campaign, but no ministers were available to be interviewed.
Conservative MPs were angry about the situation that No 10 got into by holding a party, denying one had taken place, and then maintaining that denial despite the video obtained by ITV.
Sir Roger said that Johnson should explain what happened at prime minister's questions later on Wednesday and warned him that it would be a resignation matter.
He said that the buck stops at the top and that Johnson's chief of staff should not be sacked.
The party was a Baron Castle moment and the government can't say one thing and do another.
His comments refer to the incident in which the prime minister's aide Dominic Cummings drove to a beauty spot to test his eyesight despite stay-at- home orders in place to contain the spread of coronaviruses.
Charles Walker, the vice-chair of the 1922 Committee of Conservative backbenchers, told broadcasters that the incident reminded him of the expenses scandal and that the government had no authority to impose restrictions in the future.
Johnson and his aides have repeatedly denied that the event held for staff at No 10 in December last year broke Covid rules.
The leaked video shows an adviser to Johnson joking with the prime minister's press secretary about a Christmas party.
The footage was shot in December of 2020. Multiple sources have said that there was a staff party inside No 10 on the Friday of December 18th, which would have broken Covid regulations at the time.
It shows the prime minister's adviser, Ed Oldfield, and other staff making a series of jokes about a party, including references to cheese and wine, and making excuses for it being a business meeting.
The fictional party was a business meeting and it was not socially distanced, according to the leaked footage.
The emergence of the video was called a "bullet to the chest" of families who have lost loved ones. Dr Saleyha Ahsan, from the Covid-19 Bereaved Families for Justice, said the saga was an example of how the government had run this from the start, with one rule for them and the rest of us having to adhere to different rules.
Ahsan said that many people around the country couldn't spend those last few days with their loved ones. It was very sad. I have been in the hospital for 14 years and have never seen anything like it.
This latest revelation is a bullet to the chest. It shows the lack of respect for the rest of us.
The Metropolitan police are considering the footage after two Labour MPs made complaints about the party and another gathering in November.
There was no event at Downing Street on Tuesday. When asked if it had changed its view, the prime minister said there was no Christmas party. Covid rules have been followed.
The Department for Education confirmed a report that some staff and the then education secretary held an office party in December last year, while London was in tier 2.
Up to two dozen staff gathered in a cafe area to drink wine and listen to a speech by Williamson. The DfE said that on that day a gathering took place to thank the staff for their efforts during the Pandemic.
Looking back, we accept that it would have been better not to have gathered in this way at that particular time.
