The U.K. minister in charge of post-Brexit negotiations has resigned in the latest blow to Boris Johnson, whose government is at war with itself over how how to respond to a surge in coronavirus cases.

In a strongly worded resignation letter, David Frost expressed his concern about the direction of Conservative Party policy, implied he was unhappy with current Brexit thinking and said the country needs to learn how to coexist with COVID-19.

He offered to quit a week ago and the pair agreed he’d move on in January, but Saturday’s report of his planned departure in the Daily Mail prompted him to exit the government immediately.