Boris Johnson was said to have been away from Number 10 at the time of the parties.
Here we take a look at what reportedly happened at those parties and the reaction to the latest revelations.
What happened at these Downing Street parties in April?
The new allegations suggest that two Downing Street parties took place the week after Philip’s death.
Advisers and civil servants gathered after work for two separate events on April 16 2021, the newspaper reports.
The two events were to mark the departures of two Number 10 staff - James Slack, Mr Johnson’s former director of communications, and one of the Prime Minister’s personal photographers.
The two parties are said to have started separately but later merged.
Witnesses told the Telegraph that alcohol was drunk and guests danced to music.
One staff member had reportedly been dispatched to a Co-op supermarket on The Strand with a suitcase to fill it with bottles of wine.
A laptop was allegedly placed on a photocopier with music blaring out and a child’s swing - apparently used by Mr Johnson’s son Wilf - was broken by a staff member.
Another witness claimed staff were worried that too much wine was being spilled on the basement carpet.
The Prime Minister is said to have left for his country retreat Chequers the previous day.
What has Number 10 said about the parties?
A Downing Street spokesperson said of Mr Slack’s event: “On this individual’s last day he gave a farewell speech to thank each team for the work they had done to support him, both those who had to be in the office for work and on a screen for those working from home.”
The spokesperson offered no further comment on the allegations that a farewell gathering was held for the Prime Minister’s personal photographer.
What has James Slack said?
The Prime Minister’s former director of communications has apologised for the “anger and hurt” caused by the leaving party.
Mr Slack, who left No 10 last year to become deputy editor-in-chief at The Sun, said the party on April 16 2021, “should not have happened at the time that it did”.
Mr Slack said in an emailed statement issued by The Sun’s publisher News UK: “I wish to apologise 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.”
What has the reaction been to the latest scandal?
Fran Hall, from Covid-19 Bereaved Families for Justice, said: “If your neighbours had behaved like this, you’d have been disgusted. For the people running the country to do it and then lie about it, shows a complete disdain for the general public.
“We shared the same pain of grieving in isolation as the Queen did. And she must be just as sickened as we are at hearing this. Sadly, instead of doing the decent thing and resigning, we can expect the Prime Minister to continue shamefully lying to our faces.
“The Conservative MPs that are keeping him in power disgrace their country.”
Sir Ed Davey, the leader of the Liberal Democrats, 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.”
His comments were echoed by Labour deputy leader Angela Rayner, who wrote on Twitter: “The Queen sat alone in mourning like so many did at the time with personal trauma & sacrifice to keep to the rules in the national interest.
“I have no words for the culture & behaviours at number 10 and the buck stops with the PM.”
Will this lead to a no confidence vote in Boris Johnson?
Andrew Bridgen, the Conservative MP for North West Leicestershire, has become the latest Tory MP to publicly announce he had submitted a letter of no confidence in the Prime Minister on Thursday (13 January) night.
He was the fifth MP to confirm that they had written to Sir Graham Brady, the chair of the 1922 Committee, calling for a vote on the PM’s future as head of the party.
Mr Bridgen told BBC Newsnight: “With a heavy heart, I have written a letter to Sir Graham Brady indicating that I have no confidence in the Prime Minister and calling for a leadership election.”
The Telegraph reported that as many as 30 letters have been submitted so far. A total of 54 are needed to trigger a vote.
What will Sue Gray’s inquiry find?
Senior civil servant Sue Gray is carrying out an inquiry into alleged lockdown-breaking events held in No 10 and Whitehall in 2020 while coronavirus restrictions were in force.
The Times reported that Ms Gray was expected to find no evidence of criminality.
However, it was also suggested that the report could censure Mr Johnson for a lack of judgment.
The newspaper said Ms Gray was expected to avoid concluding whether the PM breached the ministerial code, as this would fall outside her remit.
But she is set criticise the culture in Downing Street, it said.
A message from the editor:
Thank you for reading. NationalWorld is a new national news brand, produced by a team of journalists, editors, video producers and designers who live and work across the UK. Find out more about who’s who in the team, and our editorial values. We want to start a community among our readers, so please follow us on Facebook, Twitter and Instagram, and keep the conversation going.