Johnson is facing mutiny from his own party over the incident.

Downing Street says Cummings made the roughly 250-mile journey to his parents' property to ensure his four-year-old son could be properly cared for by relatives, if he fell ill along with his wife.

But at the time, Cummings' wife was already ill with COVID-19 symptoms. Many believe that was hypocritical given the government's mantra at the time to avoid such movements.

Cummings is the latest in a number of officials who have drawn ire over similar incidents.

Some have resigned in the aftermath.