Only the fact that the man on the door is in a prison officer's uniform and not a bouncer's tuxedo reveals that occupants are in the bowels of a category A, maximum-security jail.
Belmarsh prison's "Snooze Room" - named after its Dutch inventor Snoezelin - is at the forefront of the Prison Service's drive to reduce the number of inmates committing suicide. Prisoners go in separately, and are asked to lie on the floor and carry out breathing exercises designed to relieve stress and tension. The room is even accompanied by a "chill-out zone", converted from a padded cell, in case the inmates find the noise and colour a little too much.
Chris Plumstead, a senior healthcare officer, said: "It all looks like a Seventies disco but it really does work. It's designed to calm people down and open them up for therapy."
The Snooze Room is an example of the new philosophy that staff can intervene to improve a suicidal inmate's mental well-being. According to Kevin Lockyer, Belmarsh's deputy governor, strip cells "don't work". He said: "If you are in a deep, emotional crisis and my reaction is to take all your clothes off and put you in a bare cell, it is not going to improve your state of mind."
Prisoners receive help from professional counsellors and fellow inmates, called "listeners", who have been trained by the Samaritans.
In Belmarsh's "comfortable suite", which has been converted from two padded cells, listener Derek Bradley, who is himself serving six years, said that he had saved several lives just by giving vulnerable fellow prisoners some time and attention. "In the past, if you turned round and said you were feeling suicidal they would put you in a strip cell. So no one ever said anything," he said. "The thinking now is to encourage people to talk."