From The Observer today.

The message Johnson wanted to convey was that the MPs’ attempts to block no deal were taking the heat off Brussels. During an hour of discussions, [Greg] Clark asked for some specific details on particular issues and Johnson said someone from his office would get back to him. Later that day, Clark received a phone call from Johnson’s closest aide, Dominic Cummings, which failed to provide answers. Instead Clark found himself on the end of a foul-mouthed tirade.

According to sources aware of the exchange, Cummings bawled at him, saying: “When are you MPs going to realise that we are leaving on 31 October?” before adding: “We are going to fucking purge you.”