LONDON (AP) — British Prime Minister Boris Johnson faced a wave of public and political outrage on Tuesday over allegations that he and his staff flouted coronavirus lockdown rules by holding a garden party in 2020 while Britons were barred by law from mingling outside the home.

Opposition politicians called for a police investigation after broadcaster ITV published a leaked email invitation to “socially distanced drinks” in the garden of the prime minister’s Downing Street office and residence in May 2020. The email from the prime minister’s private secretary, Martin Reynolds, was sent to dozens of people and urged attendees to “bring your own booze.”

The event was scheduled for May 20, 2020 — the same day the government at a televised news conference reminded people they could only meet up with one person outside their household. London’s Metropolitan Police force also published reminders about the rules that day.

The police force said Tuesday it was “in contact with” the government over the party claims, which follow allegations of several other rule-breaking gatherings in Downing Street during the pandemic.

The opposition Labour Party demanded that Johnson answer questions about the allegations in Parliament — but the government sent a junior minister, Michael Ellis, to face lawmakers instead. Ellis apologised “for the upset that these allegations have caused” but said he could not comment further because an investigation was underway.

Labour Deputy Leader Angela Rayner said Johnson’s “absence speaks volumes.”

“He can run but he can’t hide,” she said.

During Britain’s first lockdown, which began in March 2020 and lasted for more than two months, gatherings were banned with a few exceptions, including work and funerals. Millions of people were cut off from friends and family, and even barred from visiting dying relatives in hospitals.

On the day of the garden party, 268 people with the coronavirus died in Britain, according to official figures, bringing total deaths to more than 36,000. The total now stands at over 150,000, the highest toll in Europe after Russia.

Johnson’s Conservative government has repeatedly been accused of flouting the rules it imposed on others during the pandemic.

The latest claims will be investigated by senior civil servant Sue Gray who was appointed by the government to look into earlier allegations that staff in Johnson’s office flouted coronavirus rules with lockdown-breaching Christmas parties in 2020.

Johnson has insisted he personally broke no rules, but British media reported Tuesday that the prime minister and his wife Carrie Johnson attended the May 2020 garden gathering.

Health Minister Edward Argar said he understood why people would be “upset and angry,” but said he would not “pre-judge” the outcome of Gray’s inquiry.

But Labour lawmaker Ed Miliband said the allegations were “incredibly damning” and said Johnson must explain whether he attended the party.

“How can he lead the country through these difficult times, get people to follow public health advice, if he has so flagrantly breached the rules?” Miliband said on BBC radio.