LONDON: British Prime Minister Boris Johnson apologised and vowed to "fix it" after a report on Monday into lockdown parties held at his Downing Street residence criticised serious failures at the heart of government.

A report by senior civil servant Sue Gray into lockdown-breaking gatherings at Downing Street under Johnson condemned some of the behaviour in government as being "difficult to justify".

"I want to say sorry," Johnson told parliament. "Sorry for the things we simply did not get right and sorry for the way that this matter has been handled."

Johnson said the government had to learn from the criticisms raised, and that he would make changes to his Downing Street operation.

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"I get it and I will fix it," he said. "And I want to say to the people of this country. I know what the issue is, it is whether this government can be trusted to deliver and I say yes we can be trusted, yes we can be trusted to deliver."