Dominic Cummings, the former chief adviser to Boris Johnson who fell foul of lockdown rules, will face questions at the Covid-19 Inquiry.

A key figure in Downing Street throughout the Government’s early response to the pandemic, Mr Cummings will give evidence on Tuesday as the investigation continues.

Mr Cummings was Mr Johnson’s top political aide in Downing Street from July 2019, having previously led Vote Leave in the Brexit referendum and worked on the Conservatives’ 2019 election campaign.

He was asked to leave government by then-prime minister Mr Johnson in November 2020, months after it emerged he had taken a lockdown-breaking trip to County Durham with his family.

Mr Cummings made the journey by car from London at the end of March 2020, when the Government had instructed people to stay at home, and returned in April after driving to Barnard Castle, County Durham, amid concern that catching Covid had affected his eyesight.

Lee Cain, the former Number 10 director of communications who left government a day before Mr Cummings, will also appear at the inquiry alongside his close ally.

The two men will give evidence a day after Martin Reynolds, the civil servant dubbed “Party Marty” due to his role in the partygate scandal.

Speaking on Monday, Mr Reynolds apologised and said that Government protocols were “inadequate” and “grossly deficient” in the early days of the pandemic.

He said there was an “unusual dynamic” in No 10 during that period, and he turned on the “disappearing message function” on a WhatsApp group titled “PM Updates” in April 2021 because of concerns about potential leaks.

Mr Johnson meanwhile came in for criticism from the UK’s top civil servant, Simon Case, who vented that he “cannot lead” and was making government “impossible” in WhatsApp messages given to the inquiry.

Appearing on Tuesday’s morning media round, roads minister Richard Holden said “tittle tattle” is “not the important issue”.

“If there (were) conversations between people and they were recorded throughout history as they are on WhatsApp then would it be similarly embarrassing? You know, would (Sir Winston) Churchill and (Neville) Chamberlain have faced a similar… what their colleagues said about them on X or Y day? I’m absolutely positive they would have done. I think that’s tittle tattle. I don’t think that’s the important issue here,” he told Times Radio.

Extracts from the notebook of Sir Patrick Vallance meanwhile showed the chief scientific adviser considered the ex-PM to be weak and indecisive.

He also believed senior officials in Number 10 had tried to “strong arm” him and Professor Sir Chris Whitty into appearing at a press conference around the time it was disclosed Mr Cummings had gone to Barnard Castle.

Some of those bereaved in the pandemic will be standing outside the inquiry on Tuesday ahead of Mr Cummings’ appearance, holding pictures of loved ones who died.