I think a gradual approach is better and it's not just about masks. The danger is if you go bang straight back to the way it was overnight with no restrictions anywhere, particularly in London with people being "ordered" back to the daily rush hour.
As i said this isn't a calculated choice he's made, it's a choice he's been forced to make and its a roll of the dice due to his own stupidity and is a desperate attempt to win the public back.