British Prime Minister Boris Johnson on Sunday defied pressure from within his own party and backed top aide Dominic Cummings over allegations he breached coronavirus lockdown rules.

Cummings has been a highly divisive figure in British politics since masterminding the successful 2016 Brexit campaign alongside Johnson.

Mr Johnson gave a public show of support to his embattled aide, saying he acted with “responsibly and legally and with integrity”.

But Johnson rejected calls to sack him after he came under fire for travelling across the country with his wife while she was suffering from symptoms of the disease when the official advice was to isolate at home.

Johnson said during Sunday’s news briefing he believed Cummings “acted responsibly and legally and with integrity” after the pair held crisis talks.

“I’ve concluded that in travelling to find the right kind of childcare at the moment when both he and his wife were about to be incapacitated by coronavirus, and when he had no alternative, I think he followed the instincts of every father and every parent,” he added.

Cummings was seen with his son close to his parents’ home in Durham, northeastern England, more than 250 miles (400 kilometres) away from his London home on March 31, the day after he himself reported suffering symptoms.