This graph explains what it is they're going for. Basically, they're trying to keep the health system below saturation, but busy, in the hope of chugging through the "inevitable" number of cases at a sustainable rate.

Of course, that requires them to be able to "apply the brake" appropriately to keep things from becoming saturated. Which is why I thing the best word to describe the attitude of the UK government is "ballsy".

EDIT: Link to the original Lancet article the figure is from

https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

The risk of overly-strict measures is the blue line; the aim of the UK government is to go for the green line.