In the USA in the area where I live, the guy at the door at Walmart was marking down on a pad, the number of people who are NOT wearing masks. Last week he was a bit cocky authoritative regarding the order to wear masks. This weak he was humble, letting me actually assist with operations at the door, even though I don't work there.
It has to do with statistics, and with the fact that the push by government is letting government see that the people can only be pushed so far.
Both here, and in the UK, if there is an unknown, like Covid was months ago, Government is required to take precautions for their people. But in both countries, when they find out that there is no need for such measures, they are required to let the people be free.
In the USA, the time that Government can regulate us under something like marshal law, is different for different States. But is probably at a 90-day max for a few areas, and 30-day max for most areas. Well, it's well over the 30-days, and there aren't any people falling dead around us on the street or in the store. So, government has to back off.
If government won't back off, people in both the USA and the UK have the ability to take government people to court for disturbing the peace in fake pandemics. Man-to-man is different than going to court against government.
In other words, if the British prime minister hits you with his car, you have the right to sue him in his non-government capacity. In the same way, if something he does messes with your freedom, you have the right to sue him over it.