Local MPs insist Boris Johnson's claim that he did not know he was breaking his own government's rules when he attended an illegal party is no defence.

The Liberal-Democrat MPs for Richmond Park and Twickenham have backed the calls from the party leader, Ed Davey, who represents Kingston, for the Prime Minister to resign.

Boris Johnson's explanation of his appearance at a Downing Street – bring your own booze – party during lockdown in May 2020 was that no-one told him it was against the rules.

Today, the Richmond Park MP, Sarah Olney, said ignorance of the law is not a defence, particularly as the Prime Minister actually set the rules in the first place.

She pointed to the case of a London woman who briefly visited a friend she helps with child care to deliver a birthday card. She did not enter the property, but other people were present and she was prosecuted for attending an illegal party.

In her defence, she said she did not intend to break the Covid rules, however, she was fined £250 in a magistrates court.

The MP said the case was 'useful context' when set against Boris Johnson's claims that he did not realise he was attending a party in his garden Downing Street.

Separately, the Prime Minister stands accused of knowingly misleading the House of Commons by telling MPs that there had been no parties in Downing Street. Apart from the event on May 20, he has apologised to the Queen over two leaving do parties at Downing Street, including music, dancing and drinking, on the eve of Prince Philip's funeral.

Mr Johnson's claims that he was ignorant of the party culture in Number 10 has been unravelling with a number of sources saying he was warned that these events were potentially illegal and wrong. Tory backbench MPs are pushing for a vote for his removal, while some Cabinet ministers are putting together leadership campaigns.

Sarah Olney said: "Every day Boris Johnson stays, he's doing damage to the country and its international reputation.

"Working families are facing soaring energy bills and tax hikes while their wages remain stagnant. This should have the government's full attention, but instead they're caught up in a farcical circus of in-fighting, plotting and dishonesty.

"Everyone who worked at No.10 seems to have been continuously partying throughout lockdown. Extraordinary."

Lib-Dem leader, Ed Davey, said: "The Queen sitting alone, mourning the loss of her husband, was the defining image of lockdown. Not because she is the Queen, but because she was just another person, mourning alone like too many others. Whilst she mourned, Number 10 partied. Johnson must go."

UPDATE

Sarah Olney told Nub News: "Liberal Democrats are calling on the Prime Minister to step down after we tabled a no confidence motion on Sunday.

"Not only has he broken his own lockdown laws, he has continually misled both Parliament and the public.

"It's now got to the stage where he is recklessly undermining public confidence in the government and this country's institutions.

"It's time for Conservative MPs to show where they stand. The country deserves a chance to move on from this deceitful Prime Minister."