A lot of its regulars appeared as extras in The Killing of Sister George. A 15-minute sequence was filmed behind the green door, which was the entrance to one of London's first lesbian clubs - the Gateways, known to its denizens as the Gates. If you want to find out, all you have to do is rent a copy of The Killing of Sister George, the 1968 lesbian-themed film starring Beryl Reid and Susannah York. As the singer explains: 'When I said, 'Joe sent me,' someone laughed out loud behind the green door'. We know it wasn't always a storage space from the lyric: 'There's an old piano and they play it hot behind the green door/ Don't know what they're doing but they laugh a lot behind the green door/ Wish they'd let me in so I could find out what's behind the green door.' Even the code hidden in the lyrics - 'Joe sent me', referring to Joe Meek, the gay record producer who oversaw Vaughan's version of the song - doesn't provide much help. So why did so many people feel the need to ask? If you take a look behind it now, you'll find it's a storage space for a nearby dress shop. The green door actually exists, it's on Bramerton Street, just off the King's Road in west London.