The game is afoot after a 'Magic Circle partner' presented a stranger with a mysterious key.

Posting on Reddit, 'Lord of the Lentils' wrote "I was given a matte black key in a black pouch and was told it would open the door to a bar somewhere Central". He added, "I was given the key by a partner in a Magic Circle firm, who I'd just met". Unfortunately the Magic Circle partner vanished before specifying the location of the particular magic circle which would receive the magic key. "Does anyone have any idea what this bar could be?" asked Lord of the Lentils.

Slaughter and May partners' dining hall? A&O's stairwell?

JubJub, the secret club within Callooh Callay cocktail bar, was dismissed because the key doesn't appear to match those used by the bar. Other suggestions included "shitty viral marketing campaign", "some dudes sex dungeon in Vauxhall" and "the disabled toilets in Liverpool Street station". Most of which sound entirely plausible for a Magic Circle partner.

If you know that it opens that massive black sarcophagus they found in Egypt, or something else, chime in below.