Pioneering ‘sandless sandbags’ have been used to defuse a World War Two bomb found on a Hong Kong building site … the third discovered in the city so far this year.

The shell was buried vertically at the site of the Sha Tin-Central rail link and it took 20 hours to fully defuse the 450kg bomb.

Two-thirds of it was buried beneath mud that had hardened over the decades and more than 1,250 residents and businesses needed to be evacuated.

The bomb was upside down with its front part buried in the ground and the detonator already broken. 

Before attempts could be made to defuse it BlastSax Sandless sandbags were deployed to surround it along with a base constructed from traditional sandbags – the same way the previous bombs had been made safe.

BlastSax, which have undergone stringent MoD tests to prove their effectiveness,  are used by the military and police forces worldwide to mitigate the impact from improvised explosive devices. They can even stop bullets.

Designed to be taken to incident scenes quickly, BlastSax automatically inflate when they come into contact with water to become more effective than traditional sandbags within just a few minutes.

The American-made AN-M65 bomb, 145cm long and about 45cm in diameter, was unearthed by construction workers and is the third device found at the site this year after police defused two 450kg bombs in January.

All three were likely to have been dropped by US Navy planes between 1941 and 1945 when the city was under Japanese occupation, aiming to destroy the docks and Japanese shipping.

It is estimated that American forces dropped about 4,000 bombs on the city during the war but almost a third did not detonate.