The alarm adjacent to HMS Raleigh in Torpoint sounded on the evening of December 19, sparking concern among some local residents.
The nuclear alert siren was activated for eight minutes after somebody accidentally pressed a button, it has emerged.
Richard Clark, the deputy head of safety at the naval base, told a meeting of the Devonport Local Liaison Committee meeting that the alarm was activated inadvertently due to human error following a maintenance check.
Following “command routine maintenance” on the control system, the siren adjacent to Raleigh sounded for about eight minutes at about 6pm on December 19.
The meeting heard the siren was inadvertently activated when the system was reverted back to the normal operating mode.
Mr Clark said: “An extensive technical investigation has been conducted and that’s concluded that the siren was activated due to human error.
“The control system has an automatic timer which looks a little bit like the digital control panel of your central heating system at home. It has a number of small round buttons very close together and it’s located next to a small LED panel.
“We believe that on returning the control system back to line up after reprogramming it, it would appear that one of the buttons was pressed incorrectly, which effectively put the automatic system for the Raleigh siren to manual and in the ‘on’ position.
“The icon on the LED screen was not seen by the maintainer when he returned the system to normal line up.”
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