The 40-second TV clip from Downing Street was never meant for public consumption – and with good reason.

After its transmission, toxic footage showing No 10 staff laughing about lockdown-busting parties led to Allegra Stratton’s tearful resignation.

The leaker was also immediately pursued. Boris Johnson may have even been prompted to accelerate plans to tighten Covid restrictions.

Downing Street spent the week denigrating that employees had hosted a Christmas party with Secret Santa and nibbles last December. This was at a time in which social gatherings were illegal.

The leaked footage appeared to prove not only that the party had taken place – but suggested officials thought it was funny.

An intense manhunt is under way to uncover how the secret footage, filmed within the Downing Street complex, has become the subject of a leak.  Within 24 hours of its broadcast, the toxic footage led to the tearful resignation of its 'star' Allegra Stratton

The Downing Street compound has been the focus of an intense investigation.  Within 24 hours of its broadcast, the toxic footage led to the tearful resignation of its ‘star’ Allegra Stratton

The video showed Miss Stratton holding a mock conference to prepare for her first televised daily briefing as PM’s press secretary.

Ed Oldfield is a son of a prominent Tory donor and asked his fellow adviser to comment on Twitter rumors of a party at No 10. Also, if Mr Johnson would approve of other Christmas events.

A flustered Miss Stratton laughed at the idea and stated that she went home’ on that night. She then asked, ‘What’s your answer?

An assistant claimed that it was not a party and consisted only of cheeses and wines.

No 10 staffers in the new £2.6million briefing room then laughed as Miss Stratton tried to press on, suggesting it was a ‘business meeting’.

A thorough investigation is now underway to determine how leaked secret footage from the Downing Street Complex has been revealed.

It showed Miss Stratton holding a mock press conference in preparation for her role as the first PM's press secretary to hold daily televised briefings

This video featured Miss Stratton holding a mock media conference as she prepared for her new role of the PM’s first press secretary. She held daily televised briefings.

Miss Stratton was initially blamed for the suspicion. The ex-TV journalist was a popular figure at No10. Many of her aides felt she was treated harshly when the PM cut the televised media briefings that he asked her to lead.

However, she was an adamant foe of Dominic Cummings as well as his former chief press officer Lee Cain. She helped to remove him from office last spring.

According to one source, “You could not help but wonder if Dom had any involvement in this in some manner.” ‘He has the motive – the leak damages the PM and he loathes Allegra.

“But, he was gone at the time the video was shot and had no friends or allies in the building anymore. Is it possible he could have gotten his hands on the camera? It’s possible.’

Some have accused Miss Stratton, from No 10, of giving a horrible briefing to BBC over the PM of last month.

No 10 staffers in the new £2.6million briefing room then laughed as Miss Stratton tried to press on, suggesting it was a 'business meeting'

No 10 staffers in the new £2.6million briefing room then laughed as Miss Stratton tried to press on, suggesting it was a ‘business meeting’

On the occasion of his deplorable speech to CBI in which he talked about Peppa Pig extensively, the source stated that it was just not working. The Cabinet must wake up to demand real changes or it will only get worse. They won’t listen if he doesn’t.

Miss Stratton has repeatedly denied that she was the so-called Chatty Pig’, who briefed BBC.

Some thought that the mock conference she leaked might be a misguided effort to harm her and force her out.

The small group of employed hands that transformed the 9 Downing Street former privy courtroom into a media room quickly attracted attention.

According to one source, the footage was deleted. Another suggested the clip might have been taken from a television monitor.

‘If you look closely, you can see there is something weird about the aspect ratio – the picture looks squashed. It isn’t from an official camera – it’s someone filming it privately, maybe off one of the monitors. This looks as if someone had just kept a copy.

Many contractors were connected to ITV News where the leak surfaced. A source claimed that Miss Straton’s performance on Miss Stratton’s iPad was regularly filmed by a freelancer.

According to the source, it was discovered that the contractor had the footage even though he was gone earlier in the year. He also added: “Allegra was very worried about it.”

Stephen Gaisford is a communication specialist for Grit and helped to film the footage during the rehearsal. He denied it was being leaked.

However, he claimed that he wasn’t impressed with the Covid rules at No 10, and that he believed he contracted the virus there.

He said that he was happy with the video leak and added, “It opens a wider discussion about the behavior of those in this time period as well as the government’s responsibility towards the citizens of this country.”

“It doesn’t matter if a party was held. It all comes down to whether or not those who make the rules are actually following them. People didn’t wear masks when I went through Downing Street’s main entrance.

It was impossible to see social separation.

A source in the industry said that it was equally probable that the leak began inside No 10.

‘The video footage from these sessions was sent to nine people on email – that includes No 10 press people, staff from the events team and civil servants,’ the source said. An insider stated that the media room was not something we should have constructed. It’s cursed.

Yesterday, Mr Johnson reiterated his belief that Downing Street has not broken any rules.