U.K. Prime Minister Boris Johnson is under intense pressure to fire his controversial chief adviser Dominic Cummings for allegedly breaching lockdown rules, as public and political opinion turns against them both.

Amid a growing revolt from senior politicians in Johnson’s ruling Conservative Party, one government minister has already quit in protest at the behavior of Cummings during the peak of the pandemic.

Opinion polls show Johnson’s approval rating dived 20 points into negative territory in just four days since the furor erupted, and a majority think the aide should lose his job.