The Met Police’s investigation into lockdown breaching events at Downing Street and Whitehall has now concluded.

They have issued, or will issue, 126 fixed penalty notices (FPNs) to 83 people, with some people getting up to five fines each.

Having completed the investigation, the Met Police has now revealed details of how it was carried out and the total cost.

Sky News has broken down the details here.

Who was fined?

Detectives said they will not be revealing any names, in line with the approach they have taken throughout the pandemic.

However, Downing Street said that it understood the public interest in fines imposed on its top people so last month announced that Boris and Carrie Johnson, Chancellor Rishi Sunak and Cabinet Secretary Simon Case had all been fined.

Politics Hub: Sue Gray report likely next week after Met Police investigation concludes

What did detectives look at and how much did it cost?

The Met confirmed the investigation, which took nearly four months and was named Operation Hillman, cost about £460,000.

Twelve officers worked on the investigation full-time and others were brought in when required. They investigated events on 12 days but only ended up fining people for eight of those days.

They worked through 345 documents, including emails, door logs, diary entries and witness statements, 510 photographs and CCTV images and 204 questionnaires.

There were no interviews under caution and the questionnaires were legal documents, which the police use in similar processes.

Once the police had the physical evidence for an event they then assessed each individual.

Detectives are understood to have also taken great care to ensure they had the necessary evidence to prosecute the FPN in court if a person refused to pay it.

As COVID rules changed over the 11 months of events that were investigated, police had to ensure they were looking at the different offences at the time an event took place.

The fines covered six different types of breaches, depending on when they happened.

Why did the Met not investigate the events earlier?

From early on in the pandemic, the Met said it would not routinely investigate historic breaches of COVID regulations.

They said this was because they could not retrospectively engage and inform those breaching rules and they were summary-only offences so did not think it was a good use of police time.

The Downing Street and Whitehall events were exceptions, they said, as there was evidence that those involved knew or should have known they were breaching rules.

They also felt that not investigating could significantly undermine the legitimacy of the law and there was little ambiguity around the absence of any reasonable defence.

Which events were people fined for attending?

The Met said people who attended events on eight days were fined, however they have not specified how many people were given fines for each event. There were also two events on some of those days, and they have not revealed which of the events people were fined for.

20 May 2020 – This is the day on which Mr Johnson has admitted attending a gathering in the Downing Street garden in the first national lockdown. According to a leaked email, one of his chief aides invited Number 10 staff to a “bring your own booze” event to enjoy the spring sunshine that evening.

Mr Johnson admitted to attending the gathering with “groups of staff” for 25 minutes. But he has stressed he believed it was a “work event”.

18 June 2020 – This is understood to have been a leaving event in the Cabinet Office building at 70 Whitehall for a Number 10 official. It was said to have been attended by about 20 people, with wine allegedly drunk.

Sir Mark Sedwill, the Cabinet secretary and head of the civil service at the time, is said to have “briefly attended” and sanctioned the event.

This event was the first for which attendees were fined by the Met Police, with £50 notices sent to individuals by email on 1 April 2022.

19 June 2020 – Johnsons and Sunak fined

This was Mr Johnson’s 56th birthday. It has been claimed up to 30 people attended a celebratory gathering in the Cabinet room with picnic food from Marks & Spencer and a cake.

It is also alleged that a further gathering took place that evening in the prime minister’s Downing Street flat. Number 10 have disputed that the evening event breached lockdown rules.

It has also said that the Cabinet room gathering took place “briefly” with staff who were working that day, with Mr Johnson present for less than 10 minutes. It has also been denied that his wife organised the event or brought a cake.

13 November 2020 – The day that Dominic Cummings, the PM’s former chief adviser, left Downing Street after losing a bitter internal power struggle. It has been alleged that a “victory party” was held in the prime minister’s Downing Street flat by friends of Mrs Johnson with Abba tracks, including Winner Takes It All, being played.

A spokesman for Mrs Johnson said the claims she held a party in the flat are “totally untrue”. The prime minister also told the Commons that a party did not take place.

Another event also took place for the prime minister’s outgoing communications chief, Lee Cain, with Mr Johnson understood to have given a speech.

17 December 2020 – There are three events alleged to have taken place on this day. These include a quiz, described as a “Christmas party”, in the private office of Mr Case, a leaving drinks event also in the Cabinet Office to mark the departure of a senior member of the COVID taskforce and a gathering in Number 10 on the departure of a team member.

18 December 2020 – A Christmas party was held by Downing Street staff. In a video recording from four days after the alleged event, senior Number 10 advisers were revealed to have jokingly referred to a “business meeting” and a “cheese and wine” event.

This led to the resignation of Allegra Stratton, the prime minister’s press secretary. According to reports, around “40 or 50” people crammed “cheek by jowl” in a room in Number 10 for the event.

14 January 2021 – This has been reported as a “prosecco-fuelled” leaving do for a Number 10 aide during which Mr Johnson is alleged to have given a speech thanking the official for their work and staying for around five minutes.

16 April 2021 – On the eve of Prince Philip’s funeral – for which COVID rules obliged the Queen to sit alone during the service – two parties are reported to have taken place at Number 10.

It has been claimed around 30 Downing Street staff drank alcohol into the early hours at the two events, with one attendee said to have gone to a nearby supermarket with a suitcase they filled with bottles of wine.

A staff member is also alleged to have used and broken a swing in the Downing Street garden belonging to Mr Johnson’s son, Wilfred. Number 10 said Mr Johnson was not in Downing Street that day.