The Prime Minister’s father, Stanley Johnson, was pictured shopping without covering his face, breaking current Covid-19 restrictions.
Mr Johnson – a former Tory MEP – apologized, saying he might not be “100% aware” of the current rules after returning from abroad.
Fines for not wearing a blanket in a store were raised by the government last week to £ 200 for first-time offenders.
Former Labor leader Jeremy Corbyn has also apologized for breaking the rules.
He was pictured at a dinner party that appeared to have nine guests, going against the government’s “six rule”.
Asked about the photos, Boris Johnson’s official spokesperson said it was now up to the police to “determine what action to take,” adding: “What the Prime Minister is clear on is that the rules apply to everyone and that everyone must follow them ”.
The Prime Minister’s father was seen in a West London newsagent on Tuesday without a mask, the photo first appearing in the Daily Mirror.
It came a day before her son, Boris Johnson, held a press conference, calling on the public to “follow the rules” and warning fines would be imposed on those who do not.
Speaking to the Mirror, Stanley Johnson said: “I am extremely sorry for this mistake and urge absolutely everyone to do everything they can to ensure that they are following the rules regarding masks and clothing. social distancing.
“The fact that this is my first day back in the UK after three weeks abroad is, I’m sure, no excuse for not knowing the rules. ”
A Downing Street spokesman said the Prime Minister’s father “fully understands the vital importance of everyone playing by the rules”.
Mr Johnson was criticized in July for visiting Greece during the coronavirus lockdown.
The UK Foreign Office’s air travel advice at the time advised against “all international but essential travel” and insisted on a two-week quarantine on return.
But he told the Daily Mail he was in the country “on essential business” to make sure a property he was renting was “Covid-proof” before the holidays restart.
Mr Corbyn’s photo appeared in the sun, with the newspaper saying the rally took place on Saturday.
All over England people are subject to fines starting from £ 200 for meeting indoors or outdoors in groups of more than six – although the rules are stricter in some parts of the country.
The North London MP told the newspaper: ‘I recently had dinner at a friend’s house where the number of guests finally passed five.
“I understand that staying at dinner was a violation of the rule of six. I apologize for my mistake. ”
Responding to the picture, Labor leader Sir Keir Starmer said: ‘We all have to obey the rules, Jeremy knows I know we all have to obey the rules.
“I’ve said all along that whatever government rules we should all follow. We have a duty to do it. ”
Asked whether Mr Corbyn should be fined, Sir Keir told reporters: ‘It’s not for me to decide who should be fined, but for me to say that everyone must follow the rules. ”
It is not known whether Mr Johnson or Mr Corbyn were fined.