When 2 serial liars tell lies about each other it's impossible to tell the truth without hard evidence to back it up. Let's just say, for all his scumminess and lying, Cummings seems to be producing more evidence to back it up than Johnson, who seems to simply be blustering and denying but can't support a single thing he says. Also you have 2 ***** who were happy to screw over the country, 1 jumps ship and starts badmouthing the other, that doesn't stop the one still on the ship from being a twat.
Now why is the singular of twat fine but the plural not? Funny old system.