There seems to be only a few decent photographs of this place, so it's nice that Robert Clouse (the director) managed to feature it quite prominently in this film - possibly not too long before its eventual demolition and the areas redevelopment into the Fo Tan train depot. The building features in the film as a drugs lab that gets raided by the police.
Ma On Shan in the background
I may have gone a bit overboard with the screencaps here, but I think any shot of this long forgotten building is worth putting up.
I'm not sure if the school sign on the roof was authentic or not, simply because I can't find any useful information on the place, but in the film the building is referred to as an abandoned school.
Mitchum goes back at night to case the joint and gets inside. The following night time shots are from this scene, but I have no idea if they were filmed on location or in a the studio. I'm going to take a gamble and say they were on location simply because I am an optimist...
I've put a location link in this post (it can be found at the bottom), based on Thomas' comments below (i.e. Block 6 Jubilee Garden)