British Prime Minister Boris Johnson on Monday failed to draw a line under a scandal over his top aide Dominic Cummings allegedly breaching coronavirus rules as pressure mounted on the Brexit mastermind to go. Johnson faces the threat of his government’s authority being undermined in the heat of a health crisis that has claimed nearly 37,000 lives in Britain and thrown one of the world’s top 10 economies into its biggest downturn of modern times. Cummings was already a lightning rod for many Britons over his role in orchestrating the 2016 Brexit campaign that eventually saw Britain pull out of the European Union after nearly 50 years on January 31.