Boris Johnson did not think coronavirus was a “big deal” as he focused on other concerns just weeks before the first lockdown, Dominic Cummings wrote at the time.

Mr Cummings, who was the then-prime minister’s chief adviser, messaged colleague Lee Cain saying Mr Johnson thought the main danger was talking the economy into a “slump”.

The WhatsApp message from March 3 2020 was shown to the UK Covid-19 Inquiry on Tuesday as Mr Cain, who served as No 10’s communications director, gave evidence.

Mr Cummings wrote: “He doesn’t think it’s a big deal and he doesn’t think anything can be done and his focus is elsewhere, he thinks it’ll be like swine flu and he thinks his main danger is talking (the) economy into a slump.”

Twenty days later, on March 23, Mr Johnson ordered the UK into lockdown to slow the spread of coronavirus.

Mr Cain told the inquiry that, in January and into early February, other things like Brexit, 5G and a Cabinet reshuffle were the focus in Downing Street.

He conceded that the Government got the assessment of the virus “wrong” before it arrived in the country in early 2020.

Under questioning from counsel to the inquiry Andrew O’Connor KC, Mr Cain said: “The view was the UK was incredibly well prepared, there had been a decade of pre-preparedness and we were amongst the best in the world to deal with a pandemic and it was being monitored closely by officials in the Department of Health.

“So I think it was quite rational at that point to think it was a departmental lead and they would continue to inform us as and when required and when it needed more attention.

“You can see it goes up the agenda in Number 10 as we move through January and into February.

“Clearly we got that assessment wrong, but I think you can see why we made the judgments that we did at the time.”

Mr Cain’s written statement noted that Mr Johnson did not attend at least four Cobra meetings, focusing on other issues and taking a two-week holiday.