Updated

In several of the chilling social media videos taken during the panic-stricken moments shortly after the Manchester Arena bombing an automated public address announcement can be heard calling on an “Inspector Sands” to “please report to inspect and control.”

It is Britain’s version of a fire alarm – some reports claim that old theatres used it when a fire broke out because shouting “fire” would cause a panic, and sand buckets were used to put out fires.

Today the “Inspector Sands” alarm can be heard in times of trouble including terrorism anywhere in England from railroad stations to airports.

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A Freedom of Information request fulfilled in 2011 by the British Government and posted online explained, “The Inspector Sands message exists so that we can get staff prepared to carry out certain safety related activities without causing unnecessary alarm for customers. The message gives us an opportunity to investigate why the fire alarm is operating.”

In the case of the Manchester Arena terror attack, the alarm can be heard while hundreds of children are stampeding out the exits, and some are climbing over barricades, to get out of harms way.

On the other hand, London Underground users report hearing the “Inspector Sands” alarm fairly regularly in this age of terror alerts.  As one wrote in the Daily Telegraph in 2003, “there can hardly be a single regular traveler on public transport who doesn’t realize the urgent presence of Inspector Sands means the nearest officer from Special Branch or the Bomb Squad should go immediately to the place specified.”

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Far from causing a panic, the alarm, the writer says, causes “seasoned commuters to look at each other and smile. They are trying not to frighten us. But we know exactly what they mean.”