A Cabinet minister was heckled after branding Angela Rayner “toxic” and accusing her of asking loaded questions in the style of “when did you stop beating your wife”.

Kit Malthouse, the Chancellor of the Duchy of Lancaster, came under fire in the Commons as he made the comments in response to concerns of a “cover-up” over the Covid public inquiry.

Labour deputy leader Ms Rayner acknowledged the country has reached the “dark milestone” of more than 200,000 Covid-19 deaths, telling Mr Malthouse: “The Prime Minister delayed the start of the public inquiry into the Government’s handling of the pandemic, with the hearings not expected until 2023, making a full inquiry unlikely before the next election.”

Ms Rayner highlighted reports suggesting the Government is “trying to block evidence to the inquiry, with ministers fearful they could be sued for damages”, adding: “There can be no hint of a cover-up or excuses for ministers dodging scrutiny.

“Does he deny those reports that have been in the press and, if not, how can he assure us and the public that process will be independent?”

Mr Malthouse, to heckling from the Opposition benches, replied: “Well, the honourable lady has her very own brand of toxic which she attempts to pump into everything the Government does and she’s effectively, no, no, no, no, we literally can’t conduct debate in this House on the ‘when did you stop beating your wife?’ questions.

“This inquiry will be one that will be independently chaired and thoroughly conducted. It will have statutory powers to summon evidence and witnesses in the way that others have done.”

Mr Malthouse said the Government is “determined to learn the lessons of the Covid pandemic”, adding: “Nobody thinks that everything that happened during the pandemic was perfect.

“But to start her contemplation of this issue by maligning the motives of those ministers who put their shoulder to the wheel at a time of national emergency is frankly disgraceful.”

Mr Malthouse earlier told MPs “I own a young man in his 20s” – before acknowledging it is his son.

Conservative MP Lee Anderson (Ashfield) pressed the minister to ensure civil servants are back in the office.

Mr Malthouse replied: “We do want to see as many people as possible back in the office, not just because it’s more efficient, not just because we think it’s a better way for Government to operate, but also because we all, importantly, have a duty to the young.

“It is impossible for the young to acquire the skills and the abilities that they need when they are working remotely.

“As somebody who has someone in their 20s, well, I own a young man in his 20s, my son, I know how debilitating it would be for those who are starting their career to operate from their bedrooms.

“Those of us in senior positions have a moral duty to be present in person with them to give them the skills and abilities they need to advance their careers.”

Cabinet Office colleague Jacob Rees-Mogg also appeared to blame civil servants working from home for delays in public services for items such as driving licences and passports, saying technology is “unquestionably the answer” to reduce delays.

Labour MP Chi Onwurah MP (Newcastle upon Tyne Central) said: “Passport delays, driving licence delays, benefit delays, visa delays, which bit of backlog Britain is he going to break further in order to slash the civil service?”

Mr Rees-Mogg said: “The honourable lady is confusing two different things. There haven’t been reductions in the Passport Office. These are proposed reductions.

“What is going on is that too many people are still working from home. We need to get people back in the office doing their jobs. But we can also do more with fewer people.”

Answering a similar question from Labour shadow Cabinet Office minister Rachel Hopkins, Mr Rees-Mogg said: “What we are trying to do is to get back from the Covid backlog.

“It is undoubtedly the question, the fact, that because people have not been going into their offices – if you take DVLA, the mail wasn’t being opened, it was piled up in room after room because people weren’t going in… to the office.”

He said that was a combination of Covid requirements but also the “excessive rules” of the Welsh Government, adding: “This backlog has to be dealt with, but technology is unquestionably the answer.”