500kg WWII bomb found in Plymouth garden safely detonated at sea by Royal Navy

A Second World War bomb that forced thousands to evacuate their homes in Plymouth has been detonated at sea by Royal Navy divers who planted an explosive charge on the device.

The 500kg German munition was discovered in a garden on St Michael Avenue on Tuesday, prompting "one of the largest UK peacetime evacuation operations", according to the Ministry of Defence.

On Friday, a military convoy transported the unexploded bomb on the back of a truck to Torpoint Ferry slipway near the HMNB Devonport base, where it was taken out to sea.

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The device was then towed behind a Navy vessel and submerged to a safe depth where it was successfully detonated at 21:51 GMT.

The disposal team comprised members of the Army's 11 EOD & Search Regiment, who are often the first responders from the Armed Forces when called upon by local authorities to assist with unexploded munitions.

They were supported by elements from 35 Engineer Regiment (EOD&S) who provided vital mitigation measures at the immediate location of the munition, and 42 Engineer Regiment (Geographic).

Since the first discovery of the bomb, around 30 of the Armed Forces' most experienced bomb disposal specialists had worked around the clock to establish the condition of both the explosive payload contained within the bomb – and the status of its fuse – before further action could be taken.

If either had significantly degraded, it may not have been possible to move the bomb and there would have been a significant risk of an uncontrolled explosion – with several residential houses within the projected blast radius.

After careful assessment of the munition, which was identified as an air-dropped German bomb from the Second World War, designated SC-500, it was decided that moving the bomb would present the lowest risk.

Around 10,320 people and 1,219 properties were affected by the 300m cordon placed along the route as it was transported to sea.

The Defence Secretary thanked the personnel who had been involved in the "highly complex operation".

Grant Shapps said: "I would like to express my thanks to all our personnel involved in this highly complex operation, who worked both night and day this week to keep the public safe and minimise the risk of damage, as well as the public for their patience and co-operation.

"The success of this operation is testament to the level of skill and expertise across our Armed Forces, as well as the bravery and fortitude of our personnel when faced with high-risk situations and working under extreme pressure."