Hardly a day goes by without another revelation about Downing Street parties during the Covid lockdowns. Each new bombshell leaves another crater of questions about what was going on, how it was allowed to happen, who knew and what happens next?
Below, we attempt to answer these questions and others:
Why are we only learning of the parties now?
The earliest allegation of a government lockdown gathering (so far) dates back to 15 May 2020. But reports of the parties only started appearing in the media in the winter of 2021.
The Daily Mirror's Pippa Crerar - who first broke the news about two parties, in November, - said she first heard rumours of Christmas parties back in January 2021 but wasn't able to substantiate them until months later.
People leak stories to journalists for all sorts of reasons - to damage a political rival, for revenge, for fun. But without knowing the identity of the first leaker, it is hard to say why they leaked and why they waited so long.
What we do know is that the Mirror's first story in November encouraged others to come forward with their own party experiences and almost a month later new tales are still emerging.
Were these parties work or social events?
Some were social events - including the 20 May 2020 drinks attended by the prime minister, that led to his public apology this week. How do we know? Because ITV obtained the email that had invited staff to "bring your own booze" to "socially distanced drinks in the No 10 garden".
However, Boris Johnson has insisted he believed "implicitly that this was a work event" arguing that the No 10 garden was often used "as an extension of the office".
There have also been questions about the nature of an event on 15 May 2020. A picture published by the Guardian shows about 19 people, including Mr Johnson and his wife, sitting in the garden with bottles of wine and a cheeseboard. The prime minister said this picture showed "people at work, talking about work".
Will we hear about more parties?
The number of stories swirling around have led some to wonder if there was a single day during the pandemic when a party wasn't taking place in No 10. At least 10 alleged gatherings, in Downing Street or government departments, have come to light so far. If you're a details person, here's the full list
Will there be more? If the last month is anything to go by, then probably.
What can Sue Gray's report cover and rule on?
Following the first few reports of parties, the prime minister ordered an investigation to establish the facts.
Many Conservative MPs have said they will wait for the results of that inquiry - being led by senior civil servant Sue Gray - before passing judgement on the prime minister. Ms Gray's report is likely to be a largely factual account of parties held in Downing Street.
Catherine Haddon, of the Institute for Government think tank, says Ms Gray is unlikely to assign individual blame, but her report "might refer disciplinary action to others". It may touch on the role of the prime minister, but it is not Ms Gray's place to judge his behaviour, she adds, although the "bare facts alone" may be damning.
Did the prime minister or others break the law?
Sue Gray cannot rule on whether lockdown laws were broken - but the question is key to the prime minister's future. If the inquiry uncovers evidence of behaviour that is potentially a criminal offence, it will be referred to the Metropolitan Police and the inquiry will be paused, according to its terms of reference.
What is Dominic Cummings' role in all of this?
The PM's senior ex-aide-turned-massive-thorn-in-his-side was one of the first government figures to be accused of breaking Covid rules. He drove from London to County Durham at the height of the first lockdown, later arguing that the move was prompted by security concerns.
More recently he has been making allegations about rule-breaking in No 10 during the pandemic - including writing in a blog about the drinks on 20 May 2020.
Mr Cummings says he warned at the time that the event "seemed to be against the rules".
Who was invited to the garden drinks on 20 May?
An email from Mr Johnson's principal private secretary, Martin Reynolds, inviting people to "make the most of the lovely weather", was sent to a distribution list of around 100 people. But the full list of recipients has not been published.
So why does it matter who was on the list?
Well, the names will show who knew about the party taking place.
Could an invitation go out without with PM's permission?
Downing Street has said Mr Johnson did not see the email inviting staff to the drinks.
But many Westminster-watchers are sceptical.
On Tuesday, Caroline Slocock, who worked in the private offices of Margaret Thatcher and John Major, told BBC Radio 4 it was "inconceivable" the PM wasn't aware of such an invite, especially one from a close staff member using the word "we".
Hannah White, of the Institute for Government think tank - a former secretary to the Committee on Standards in Public Life, said she believed the PM "had to have" known about the event.
Who else attended the party?
One of the next steps is to find out who went to the gathering, despite the lockdown . The BBC has been told from sources at the garden drinks that around 30 people were present, alongside the PM and his wife.
Who went to the party will be key for the same reason as the invite list, showing who knew about the event.
But more importantly, the attendee list will show who decided to break the rules - and perhaps the law - individually.
Could Mr Johnson really not have known about other parties under his own roof?
Downing Street itself is a complex series of interconnected houses turned, over the years, into an unusual combination of living and working spaces.
Chancellor Rishi Sunak lives in the flat above No 10 Downing Street. Mr Johnson, wife Carrie and their two young children live in the larger flat above No 11.
Is it plausible that both men would have been unaware of gatherings in the building that is both their home and their place of work?
Are Downing Street staff allowed to drink at work?
The civil servant management code doesn't mention alcohol or prohibit drinking in the office.
Peter Caldwell - who worked as a government special adviser between 2016 and 2020 - told the BBC News that before the pandemic he would often have a drink in Downing Street on Friday evenings.
BBC political correspondent Ben Wright, who has written a book about the drinking culture in Westminster, says alcohol "has sloshed through the history of political life for centuries".
"Drink enhances the exhilaration of political success and numbs its disappointments. It unknots in moderation and unbalances in excess.
"Prime ministers have grappled with this for years, from the port-dependent William Pitt the Younger, through to Herbert Asquith, Winston Churchill, Wilson and even Tony Blair, who described alcohol as a "prop" in his memoir."
How many wine bottles can you fit in a suitcase?
The latest revelation - published by the Telegraph - includes the detail that staff were reportedly sent to a nearby shop with a suitcase, that was brought back "filled with bottles of wine".
How many might that be? Following a very unscientific experiment - how big is a suitcase, after all - we found we could fit roughly around 30 bottles, or possibly one Nebuchadnezzar, in a medium-to-large suitcase.
Although it would be less if you wanted to pad out the bottles to avoid breakage.
And would there be room for snacks? Do you sacrifice a bottle of wine for a family-sized pack of crisps?
The research continues.