Unstable fuses could cause unsalvaged World War II bombs aboard an abandoned shipwreck in the river Thames, UK, to blow, reveal investigations by New Scientist.

The remains of the ship today. Tick...tick...tick...

For 60 years the people of Sheerness in Kent have been living next door to a 1400-ton (2.8 million pound) time bomb. A lethal mixture of unstable second world war bombs is in the rusting wreck of the SS Richard Montgomery, a US cargo ship that lies half-submerged on a sandbank in the Thames, only two kilometres from the Kentish town.

If the wreck explodes it will be one of the biggest non-nuclear explosions ever. The cargo contains a mixture of fused and unfused bombs that were destined to support the Allied push in France following the D-Day landings.

For the first time a New Scientist investigation has established that UK government explosives experts believe that some of the fuses are unstable. Even a small shock could cause one of them to detonate, setting off part or all of the rest of the cargo.

More SS Richard Montgomery Facts

Deadly cargo

The investigation has uncovered official estimates of the devastation that the explosion would cause, including predictions of a three kilometer high column of water, mud, metal and munitions sent into the air by the blast. That is equivalent to the height of nearly 7 Sears Tower buildings stacked on one another. See graphical comparison below.

Five years ago the government asked independent consultants to carry out a risk assessment of the wreck. The consultants said that the safest course of action would be to remove the wreck's deadly cargo.

In 2001 the government held a meeting in Southampton to discuss what should be done about the wreck. But three years later this risk assessment remains unpublished and the Richard Montgomery remains on its sandbank, slowly rusting.

This is what the estimated blast height would be in comparison to the Sears Tower in Chicago shown at lower right in image.