The x ray machine sounded a tone and my bag remained inside while the x ray image was scrutanised. The bag was then removed via the conveyor and she searched if fully, giving most of my things a cursory swab until she found the psp case. She showed me the results of the swab on a monitor and explained to me that she was satisfied I had no dangerous items and I was free to continue through to the departure lounge. She never told me what she was looking for but the screen she referred to had 2 green bars on it - the first bearing the acronym 'COCA' and the 2nd 'HRN'. I know that the machine must have picked up a trace of heroin as Id used the playstation case to stash an 8 ball in the car a week or 2 previously.
My guess is that if either of those bars had been red, I'd still be getting my bum fucked in Wormwood Scrubs now......