Having re-read the transcript of Johnson's press conference yesterday, you have to say that this a bold move. I have seen many describe it as a gamble, but what it really is, is a trade.
The Government are clearly happy for there to be a very high infection rate and they want this entire ordeal to be over with, quickly. There are two benefits to that: firstly, you minimise the economic impact that would inevitably occur with the prolonged use of highly-restrictive quarantine measures. Secondly, you quickly build up some measure of immunity in the population, making them more resistant to a second wave next winter. The price of those benefits, is a much higher death rate. That's the trade.
To put the Government's numbers in some context, Sir Patrick Vallance said that 50% of the total infections that will occur, will occur three or four weeks either side of the peak (which, on Government estimates, will be mid-June). The upper threshold for total infections in the Government's scenario modelling, is 80% of the population becoming infected. That means that some 40% of the total UK population could be infected with Covid-19 during the six week period from late May to early July - that is 26 million people.
If the Chinese CDC numbers prove accurate, then we can expect 14% of those people to require hospital treatment of some sort and 8% of them to require intensive care - that is 2 million people that will require an ICU bed for critical life-saving treatment in the month of June. The UK has a total of 4,000 ICU beds (which are already 80% full). June, according to the Government's own numbers, is going to be absolutely horrific. In terms of casualties, we're essentially talking the opening day of the Battle of the Somme, every day, for more than a month. I can scarcely imagine the absolute hell that awaits NHS critical care doctors this summer.