The footage shows a group of cloaked men gathering in a courtyard around a statue at the facility in Geneva, Switzerland.

But CERN has declared that the video is fake, and claims that the ritual was simply researchers and scientists coming to work at the facility ‘taking their sense of humour too far.’

The facility is home to the world’s largest and most powerful particle accelerator, known as the Large Hadron Collider.

Its aim is to allow physicists to test the predictions of different theories of particle physics.

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It first started up on 10 September 2008 and was built over a decade by over 10,000 scientists and engineers from over 100 different countries.

In the clip, there appears to be at least eight figures standing in the shadows, before one man moves into the centre of the group.

Moments later, a woman wearing a white dress enters and kneels on the stone floor.

Viewers of the footage speculate the man is holding a knife which he appears to plunge into the woman’s chest before the clip suddenly cuts off.

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In the background, a man recording the mysterious ritual – who also appears to be wearing a cloak – can be heard swearing loudly as he watches the horrifying scene.

The video was uploaded to YouTube by ‘Richie from Boston’ who wrote: “This is new footage caught on the grounds of CERN, videotaped from inside the building.

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“If it’s real, that’s horrible, if it’s a staged ritual, that’s equally bad.

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He later added: “So it turns out the origin of the video posted for the sacrifice at CERN has been found – the problem is, the man is dead. Now hoax or no hoax, let me remind you all we have seen this before and we know all that expose this evil are killed or made to disappear.”

A spokesman for CERN told Mirror.co.uk: “This video is a work of fiction. CERN fills up with visitors over summer, with users from across the world who come to CERN as part of their work, and some of whom occasionally let their sense of humour go too far.

“That is what has happened on this occasion. CERN does not condone this kind of spoof.”