Dominic Cummings was “the most empowered chief of staff Downing Street has seen” and brought an “unusual dynamic” to Number 10, the UK Covid-19 Inquiry has heard.

Mr Cummings, then-prime minister Boris Johnson’s former chief adviser, became well-known to the public when it emerged he had driven to County Durham beauty spot Barnard Castle during the first lockdown.

He is due to give evidence to the inquiry on Tuesday.

His name was repeatedly referenced in Monday’s session, as Mr Johnson’s then-principal private secretary Martin Reynolds described the power he believed Mr Cummings was able to wield in Downing Street.

Giving evidence, Mr Reynolds told the inquiry there had been an “unusual dynamic around Dominic Cummings”.

He added: “In my view, he was the most empowered chief of staff Downing Street has seen and was the person whose writ ruled, who was able to drive things through the machine in the way I suspect few other chiefs of staff have done.”

Mr Reynolds described how there had been an “unease” around a so-called “shitlist” of civil servants, as the inquiry heard about the internal workings of Downing Street and the Cabinet Office before the pandemic.

Mr Reynolds said: “There was, I think, quite a bit of unease in the civil service around, and excuse my language, the so-called shitlist of people who were thought to be risks in what was perceived to be a potentially more muscular approach to the civil service.”

Mr Reynolds also rejected a suggestion made by Mr Cummings in his statement to the inquiry that the former principal private secretary was “too deferential” to Mr Johnson and had “shied away from confronting him with hard issues”.

Mr Reynolds said he had given Mr Johnson “very clear advice when I disagreed with him”, but added that those occasions related to “issues where I felt it was my role as the principal private secretary to step in and give that advice”.