Explosive threat still looms in Thames Estuary as SS Montgomery project suffers setback

Plans to remove the masts of the SS Richard Montgomery — the WWII shipwreck packed with tonnes of explosives — have once again been delayed, despite years of warnings about its deteriorating condition in the Thames Estuary.

The American Liberty Ship sank off the coast of Sheerness in August 1944 while carrying 7,000 tonnes of ammunition. Although about half was recovered, an estimated 1,400 tonnes – over 14,500 individual bombs – remain sealed inside its rusting hull.

The project to cut down the three masts, which protrude above the water near Sheppey, has been in development since at least 2020, when the government ruled that their weight could be placing additional pressure on the unstable structure below.

A Department for Transport (DfT) spokesperson said:
“Our priority will always be to ensure the safety of the public and reduce any risk posed by the SS Richard Montgomery. Experts are carrying out vital preparatory work to support any physical interactions with the wreck. We continue to monitor the site 24 hours a day and undertake detailed surveys to assess the wreck’s condition.”

However, a recent setback came after a survey in June 2023 uncovered 18 unidentified “metallic objects” on the seabed. These findings forced the DfT to reassess the viability of the contract already in place, once again stalling progress.

Southend councillor Stephen Aylen, whose ward lies just eight miles from the wreck, said:
“Why haven’t they removed the masts yet? I think that they haven’t taken them off because there’s some issue there that’s being kept quiet. Is there something on the wreck that they don’t want revealed? What’s on there? What is actually on that boat? It’s time to come clean.”

Aylen has previously raised concerns about whether the cargo could contain something more sinister — referencing the SS John Harvey, another WWII Liberty Ship, which was secretly carrying mustard gas when it sank off Bari, Italy in 1943, killing dozens when the toxic gas escaped.

He added: “The public needs to know: there needs to be some honesty as to what is actually going to happen with this ship. We saw the container ship that hit that bridge in America, and that sends us alarm bells. If that can happen with a bridge that’s been there for years, why can’t a ship sail into a few masts that are sticking up? Especially with these huge container ships coming down the Thames. We’ve had boats go into the pier!”

A 2023 Maritime and Coastguard Agency survey detected increased lean in the ship’s forward section — between 10 and 15cm eastward — raising fears about destabilisation. The report also noted that the deck near Hold 3 appears to be collapsing on the port side, suggesting worsening structural failure.

Government assessments as far back as the 1970s warned that a full-scale detonation could unleash a 3,000-metre-high water and debris column, along with a five-metre tsunami.

Though the likelihood of such an event is debated, the wreck remains under the Protection of Wrecks Act 1973, with a buoy-marked exclusion zone in place. Still, paddle-boarders, jet-skiers and yachts have been spotted breaching the area — risking serious penalties and potentially fatal consequences.

The masts were due to be removed in summer 2022, but that was delayed when live bombs were discovered on the seabed. Those were eventually removed later that year. In April 2023, the DfT said work would begin within 12 months — yet no such activity has started.