He said that, whilst understandable, the different messages in different parts of the UK – where there were different Covid rules – risked being “confusing” for the public.

He insisted that he had always enjoyed a “friendly” relationship with then-Scottish first minister Nicola Sturgeon, despite suggestions earlier in the inquiry that No 10 was reluctant for them to hold meetings.

In England, he said the tier system was “divisive and difficult to implement” involving “laborious” negotiation over local financial support.

One eye-catching revelation during Mr Johnson’s testimony came over diary extracts from Sir Patrick Vallance, his chief scientific adviser at the time.

According to one entry, the former prime minister blamed high infection rates in Wales during the pandemic on “the singing and the obesity”.

However, he was not asked about that alleged remark about Wales, which appeared in a diary extract dated 11 September 2020.

Instead, the inquiry lawyer quizzed him on a different part of the entry.