Boris Johnson has said “nobody told me” the Number 10 garden party during lockdown was “against the rules”.

The prime minister said he “humbly apologises” to people for misjudgements that were made but he would not have gone ahead with the event if he thought it broke the rules.

He said: “I’m saying categorically that nobody told me, nobody said this was something that was against the rules, doing something that wasn’t a work event because frankly, I can’t imagine why it would have gone ahead or it would have been allowed to go ahead if it was against the rules.

“My memory is going out into the garden for about 25 minutes, which I implicitly thought was a work event, and talking to staff, thanking staff.

“I then went back to my office and continued my work.”

He added that it is exactly what he has told the inquiry by top civil servant Sue Gray.

Mr Johnson admitted on reflection he “should have looked around and told people to go back indoors” after realising it was not a work event.

The PM also said he only saw the email invite for the event from his right-hand man Martin Reynolds the other day, when it was revealed to the media.