The UK’s top civil servant described Boris Johnson as a “nationally distrusted figure” during the Covid pandemic, according to the latest leaks of Matt Hancock’s WhatsApp messages.

Comments from October 2020 were published by the Daily Telegraph, as part of the latest tranche of leaked correspondence from the former health secretary.

The remarks by Simon Case and Mr Hancock appear to form part of a conversation around testing capability.

Mr Hancock writes: “I am going to get stuck in and drive this roll out. The PM is completely right on this. Delegate delegate delegate.”

Mr Case agrees: “My concern is that we can figure out how to test, what we don’t know how to do is get people to isolate.

“We are losing this war because of behaviour – this is the thing we have to turn around (which probably also relies on people hearing about isolation from trusted local figures, not nationally distrusted figures like the PM, sadly).”

The health secretary responds “sure – but even with a massive rocket up them the lorries won’t roll until late next week – so we can fix the new isolation rules between now and then”.

Mr Case was appointed Cabinet Secretary in September 2020.

A spokesperson for former prime minister Mr Johnson said: “It is not appropriate to comment on these leaks. The public inquiry provides the right process for these issues to be examined.”

The Cabinet Office declined to comment on leaks.

Northern Ireland Secretary Chris Heaton-Harris earlier insisted the trove of more than 100,000 WhatsApp messages is not the full picture of what happened at the heart of the British Government during 2020 and 2021.

He also downplayed the gallows humour and stark admissions within the messages, suggesting they show politicians “being human beings”.

One recent story suggested Mr Hancock wanted to “frighten the pants off everyone” to inspire compliance with lockdown measures among the public.

Mr Heaton-Harris denied that was the Government’s strategy.

“I think the Government strategy was to try and protect the British public as best it possibly could… and to try and give as much information as it possibly could at the right times.”

The former health secretary was also reportedly irked by the chief executive of NHS England, Simon Stevens, now Lord Stevens, during the pandemic and even said ousting him would be a “massive improvement”.

Previous revelations from the hoard of messages include Mr Hancock and Rishi Sunak’s shared belief that former special adviser Dominic Cummings’s time in Downing Street was a “nightmare”.

Asked about the evolving story portrayed in the messages, Mr Heaton-Harris told the BBC’s Sunday With Laura Kuenssberg: “It really is a partial account of what was going on and almost a view into the psyche of Matt Hancock rather than into the actual decision-making.”

The messages were shared with the Telegraph by journalist Isabel Oakeshott, who co-authored Mr Hancock’s memoir the Pandemic Diaries, which covered his time as health secretary.

Mr Hancock has condemned the leak as a “massive betrayal” designed to support an “anti-lockdown agenda”.

In a statement this week, Mr Hancock said all the material for his book have been made available to the official Covid-19 inquiry.

Ms Oakeshott has said the disclosures are in the public interest.

The Telegraph also reports on Mr Hancock’s apparent concerns over the answer to a parliamentary question regarding the role that Gina Coladangelo – the former aide with whom he had the affair that forced his resignation – had played in a G7 health ministers’ meeting in June 2021.

After being informed about the question, the former health secretary is said to have responded: “This will be another s—show if it goes wrong.”