Boris Johnson showed little regard for the guidance, even when he became ill with Covid-19.

It’s fair to say that when on March 27, 2020, the prime minister announced he had tested positive for the new disease “coronavirus”, the country experience a collective shock.

Understanding of the disease was limited, but we knew it could be very dangerous. And for him it was – it nearly put him on a ventilator and we may never really know how touch-and-go it was.

On March 27, 2020, at about 11am, Mr Johnson tweeted that he had tested positive after developing symptoms over the “last 24 hours”.

A 10 Downing Street spokesperson said he had begun to experience “mild symptoms” during the previous afternoon.

The problem is that at 8pm on March 26, Mr Johnson wasn’t self isolating, he walked through 10 Downing Street (a workplace for many) and onto the street to join the first clap for carers first the first time, noticeably socially distanced from colleague Rishi Sunak – after he began to feel ill.

This matters because for weeks people had been told to self isolate if experiencing defined Covid symptoms (at that time a continuous cough or a fever). They weren't told to carry on as normal until there was a positive test result.

When I asked Downing Street this week about the timing of the symptoms and the guidance in place, there was no denial of the previous statement that he began to feel ill in the afternoon. The reply was only a link to the tweet of March 27: “Over the last 24 hours I have developed mild symptoms and tested positive for coronavirus. I am now self-isolating, but I will continue to lead the government’s response via video-conference as we fight this virus. Together we will beat this. #StayHomeSaveLives”

I don’t know what symptoms Mr Johnson was experiencing but what is clear is that the prime minister knew he was sick and yet, seeing a PR opportunity, went outside with his chancellor to clap.

The timing of all this is also relevant because on March 26, the Coronavirus Act 2020 came into force, legislating for the country restrictions on scale not seen since the Second World War.

What followed, we all know now. Downing Street laid down the guidance and regulations, while setting them aside when it suited.

The prime minister’s reaction to recent revelations does nothing to suggest his approach ever changed.