What was the siren that sounded at Portsmouth Naval Base this morning and why was the alarm raised

The wavering tone was let off at Portsmouth Naval Base at 9.30am this morning and could be heard throughout parts of the city. It lasted for roughly one minute. It is part of the statutory tests carried out three times a year and no action is required.

The test is carried out for the Royal Navy's nuclear accident response plan for the naval base and is in accordance with Portsmouth and Gosport councils’ nuclear safety plan.

Every year the siren is sounded three times as part of the tests, on the last Wednesday of February, June and October.