Those with an elevated reading would be expected to stay at home.

Although two sweeps of the building by fire services and the police revealed no elevated readings, the incident caused havoc for travellers.

Four days following the announcement, the researchers discovered that the instrument used to measure neutrons was damaged by the heat of the liquid and gave false, elevated readings.

Furthermore, the pitot tube used to measure airspeed in aircraft can give falsely elevated readings as the pressure builds up inside the tube at high speeds.