What is the SS Richard Montgomery that sank in the Thames Estuary?

There are 2,000 cases of cluster bombs, nearly 600 bombs weighing 500lb and more than 1,000 bombs weighing 1,000lb on the boat

The Maritime and Coastguard Agency (MCA) says the risk of a major explosion is “remote”, but speculation persists.

In 1970, government tests on the site suggested a blast would hurl a 1,000ft (300m) wide column of water, mud, metal and munitions almost 10,000ft (3,050m) into the air.

The shock of the blast would shatter almost every window in Sheerness and generate a 16ft (4.87m) high wave that could sink a small craft, tests found.

In August 2004, a report in New Scientist magazine said that if the ship exploded it would be one of the biggest non-nuclear blasts ever.

Mick Hamer, who wrote the report, told the BBC at the time: “It’s as dangerous now as it has been for the last 60 years.”

McEwan is less sure. “It’s an unknown quantity,” she says.

“Some people think it’s going to decimate Sheerness and the Isle of Sheppey; others think it’s going to be a damp squib. We just don’t know.”

On its website, external, the MCA says it continues to monitor the condition of the wreck.

“Surveys are carried out by the MCA on a regular basis to ensure that any changes to the wreck, or its immediate environment, are discovered quickly,” it adds.