These pictures provide a glimpse into the tawdry swingers' club tucked away in an unassuming Derby business park.
Thousands have probably passed the entrance to The Attic, which lies among anonymous-looking construction firms and plumbing businesses at the Osmaston Road Business Park in Derby.
The deceptively large 43-room sex club is complete with an adult cinema, maze and dungeon, and even home to an ultra-realistic 'dogging' zone.
The schoolroom features a chalkboard and an antique desk, the dungeon boasts intimidating "torture" equipment, and the devil room's walls are decorated with fiery paint and a skeletal figure.
Its owner Ron Rothwell, who opened the club in 2007, charges £15 entrance for couples, £25 for single men and £10 for single women to enter and use any of the club's rooms, according to Derbyshire Live.