With regard to the current Covid-19 pandemic, it looks like the English government is (again) trying for herd immunity.
This was last tried briefly in spring 2020. There is little doubt that cases will rise, but hopefully most cases will be mild. This time around, many have been fully vaccinated. Many have had the disease and recovered. Antibodies could be much higher than spring 2020.
This is a gamble. It may not work, but it might.
Whatever happens, we cannot "go mad". The virus is still here and new variants could be imported from abroad.
I wish the English government would abandon self isolation and replace this with daily testing. This seems a far better way, with far fewer economic impacts and just as safe.