There have also been sightings by cleaners and maintenance workers of Les in the upper dressing rooms that have been disused for many years.
There have been other disconcerting moments too.
Once staff were called to the building in the middle of the night after one of the motion sensors had been triggered in the supposedly empty building, setting off the alarm.
After the police had gone Andy, along with Stuart Fraser the technical manager, found that the backstage lift had moved up a floor despite having been out of use for years and having no power running to it.
Visitors to Les's corridor by the upper dressing rooms have watched while something opens and closes the doors on request. This was seen by researchers from TV's popular Most Haunted Live, and they brought their cameras to the theatre shortly afterwards.
Theatre spokesman Iain Christie of Royal Court Theatre said: "I've seen the ghost we call Les opening and closing doors and the other stories are from trustworthy staff who have no reason to make anything up.
"I've also seen the ghost of an old woman in a red cardigan and with grey hair standing in our new Downstairsmembers' club. I thought it was one of our cleaners but she vanished when I went towards her."