Lots of people on this thread using the retrospectoscope. As a former Chief Scientific Adviser said, it is the most powerful instrument known to man. We may now think that previous scientific advice was wrong but that does not mean the scientists or politicians should have known it was wrong at the time.
Ireland closed its schools and took measures on March 12 along with many other countries across the work. The WHO had declared the corona virus a pandemic on March 11 and countries took action.
Boris Johnson, like Donald Trump, dismissed concerns. The UK waited until March 20 to close schools and implement measures.
Ireland now has had 158 deaths, i.e. 30 deaths per million.
The UK now has a significantly higher number of death from corona. It is has 5,000 deaths in hospital, i.e. 90 deaths per million, and this is not even counting a significant number of people who have died at home in the UK.
Yes, the UK should have taken action a week earlier. Neither Boris Johnson (or Donald Trump) needed a retrospectoscope to take action.