I don’t want to alarm you but if while riding on the tube you hear an announcer say: “Would Inspector Sands report immediately to security” you may be part of an unfolding terror attack.
Apparently ‘Inspector Sands’ is the bland formulation used to alert staff, but not the public, that trouble might be brewing. What you don’t want in times of crisis is an announcer going into the ‘we’re all doomed’ routine, so the fictitious inspector fits the bill.
I know about this because my 14-year-old daughter told me and as far as can be established said 14-year-old has never been wrong about anything, ever.
Following some in depth google-research on my part it seems there might be something to it. Apparently, it originated in theatres and was used in case of fire. The name Sands being selected because they used sand to put out the fire.
And now you’re thinking: For heaven’s sake Jim, Inspector Sands because they use sand to put out the fire? Well please yourself, but the 14-year-old claims to have heard the announcement twice: once at Clapham South and once as Waterloo. She came through without a scratch.
A Little London Life 
Inspector Sands is not about an unfolding terror attack, it could be anything from a pre-alarm for the fire panel or a smoke head has gone off, there are different codes for terror which is given over the radio.
Usually Inspector Sands has an instruction attached to where the location of the incident is for the shift manager to attend without having to gather further information from the controller. This is at least for us here that work for transport companies.
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