Downing Street apologized on Friday to Queen Elizabeth II over two parties held in No 10 on the eve of Prince Philip's funeral.
"It's deeply regrettable that this took place at a time of national mourning, and No 10 has apologized to the palace," Prime Minister Boris Johnson's spokesperson told local media.
The apology was made "through official channels," it was added.
At the time, Britain's coronavirus restrictions meant for indoor gatherings were banned, and only groups of six could meet outside.
For this reason, and captured in an iconic picture, the queen was forced to sit and mourn alone at her husband's funeral. Elizabeth II was married to Prince Philip, the duke of Edinburgh, for 73 years.
"You've heard from the Prime Minister this week, he's recognised No10 should be held to the highest standards and take responsibility for the things we did not get right."
Earlier on Friday, Johnson came under fire again due to two more boozy parties held in Downing Street last year.
The parties, one of which was held the night before the funeral of the queen's husband on April 17, 2021, have added to the pressure the British premier is already suffering in the hands of the opposition parties, his party's backbenchers as well as the public.
The parties came to light with an exclusive report from The Telegraph. The daily reported that "Downing Street staff drank alcohol into the early hours at two leaving events the night before Prince Philip's socially distanced funeral."
On April 16, 2021, the country was in public mourning because of the passing of the prince and flags on government buildings flew half-mast.
Queen Elizabeth II was seen attending the funeral of her husband, wearing a face mask and socially distanced from the rest of her family at Windsor Castle because of the pandemic restrictions.
Eyewitnesses "alleged that excessive alcohol was drunk, while at points, guests danced," according to the daily.
"The gatherings stretched late into the night-well beyond midnight, according to one source."
A spokeswoman for the prime minister said his former director of communications, James Slack, "gave a farewell speech" at one of the events.
Slack apologized Friday for the "anger and hurt" caused by the party.
He said: "I wish to apologize unreservedly for the anger and hurt caused. This event should not have happened at the time that it did. I am deeply sorry, and take full responsibility."
The revelation of more parties at the Downing Street during the COVID-19 lockdown has now put more pressure on Johnson, who apologized for attending a party in May 2020.
On Friday, Andrew Bridgen, a Conservative MP who has supported Johnson in delivering Brexit, said the premier should resign, joining a few other politicians, including the leader of the Scottish Conservatives, Douglas Ross.
"I will always be grateful for what Boris has achieved and his legacy should be cemented now by a dignified exit from politics," he wrote on Twitter.