It lies just beneath the surface—literally and figuratively. A rusting American Liberty ship, broken-backed and quietly corroding off the coast of Kent and Essex, barely three miles from Sheerness. To many in the southeast of England, the name Richard Montgomery is familiar, even faintly iconic. Its skeletal masts still protrude from the Thames Estuary at low tide like a warning, or a forgotten monument. But beneath those masts lies something altogether more sobering: over 1,400 tons of unexploded ordnance. The wreck is a wartime time capsule that, by all reasonable estimates, has the potential to unleash the largest non-nuclear explosion on British soil since the Second World War.
Richard Clements explains.
The wreck of the SS Richard Montgomery. Source: Christine Matthews, available here.
The story of the SS Richard Montgomery has never truly gone away. Locals have lived in its shadow for decades. Teenagers are warned off from daring swims. Journalists periodically revisit it. The government monitors it. Yet in recent months, the Richard Montgomery has once again found its way into headlines. With new sonar scans, rising concerns over corrosion, and questions about how long inaction can remain the official policy, this long-silent threat has begun to murmur again.
A Wartime Wreck with a Dangerous Cargo
The SS Richard Montgomery was built in Jacksonville, Florida, in 1943—one of over 2,700 Liberty ships constructed at speed to fuel the Allied war effort. She arrived in the Thames Estuary in August 1944, destined to join a larger convoy headed for Cherbourg, where her cargo—thousands of tons of munitions—was to support operations in liberated France. At the time, the estuary’s Great Nore Anchorage near Sheerness served as a gathering point for vessels awaiting safe passage.
While anchored there, the Montgomery’s mooring reportedly dragged or failed, and the vessel drifted onto a shallow sandbank known as Sheerness Middle Sand. Grounded and listing, the ship’s structural integrity was compromised. Efforts to refloat her proved unsuccessful. Salvage teams began offloading the munitions, but before the operation could be completed, the ship’s hull split amidships.
An estimated 6,000 tons of ordnance had been on board. Roughly half was safely removed. The remainder—some 1,400 tons by official estimates—remains inside the forward holds to this day. The cargo includes high explosive bombs, anti-tank devices, and aerial munitions, many of which have become unstable with time. A wartime manifest is believed to exist, though details have often been redacted in public summaries. Over the years, surveys have confirmed the presence of explosive material, but exact specifications are rarely disclosed in full.
The wreck was declared a dangerous site, and further salvage was ruled out for fear that disturbing the remaining cargo could trigger an explosion. Instead, the area was marked with buoys, designated an exclusion zone, and subjected to regular monitoring—a policy that has continued into the 21st century.
Living with the Risk
For most residents of coastal Kent and Essex, the Richard Montgomery is less a mystery than a fact of life—an ever-present silhouette on the horizon. Its masts, protruding from the water like the ribs of a fossilized beast, have been visible for generations. Schoolchildren grow up hearing about it. Locals give it a wide berth. And yet, for something that holds such destructive potential, it remains curiously normalized.
Signs near the shoreline warn of exclusion zones. Maritime charts mark the wreck with bright symbols. Navigation buoys flash their silent signals to passing vessels. But on land, conversation about the ship is often casual. It has become, over time, one of those shared local oddities—like a long-standing crack in the pavement or a tree that leans the wrong way. Everyone knows it’s there. Most choose not to think about it too much.
The British government has kept a close, if quiet, eye on the wreck. Annual surveys by the Maritime and Coastguard Agency check for structural shifts. A Department for Transport report in 2022 reiterated that the risk of explosion remains low so long as the site is left undisturbed. But concerns do resurface. In 2020, the Ministry of Defence released footage from a sonar scan showing the ship’s hull deteriorating, fueling public speculation.
There have been no shortage of ideas over the years—from controlled detonation to encasing the wreck in concrete. None have gained traction. Each option, it seems, carries greater risk than simply leaving it alone. Successive governments have opted for cautious monitoring rather than intervention, a decision often criticized as kicking the can down the road. Yet the wreck persists, and so does the uneasy status quo.
For those who live nearby, this balance between familiarity and latent danger is strangely British in character. Not quite forgotten, not quite feared, the Richard Montgomery remains part of the local backdrop. As one long-time resident in Sheerness once quipped to a reporter, “If it hasn’t gone up by now, it probably won’t—will it?”
Back in the Headlines
After decades of relative obscurity, the Richard Montgomery has once again captured national attention. In early June 2025, Kent Online confirmed new flight restrictions imposed over the wreck—pilots are now prohibited from flying below 13,100 feet within a one-nautical-mile radius, following expert advice aimed at further reducing risk. This no-fly rule, in effect until further notice, applies to all aircraft except emergency or coastguard flights.
The news wasn’t confined to regional outlets. National broadcasters followed with commentary on broader safety concerns, describing the wreck as “a forgotten time bomb” in one headline. Security experts noted that the estuary’s proximity to major shipping lanes—used by LNG carriers and container ships—heightens concerns not only of accidental detonation but also of potential sabotage.
Despite the growing attention, subsequent government statements have maintained a cautious posture. The Department for Transport confirmed that structural deterioration is ongoing, but insisted the risk remains low provided the site remains undisturbed. Meanwhile, maritime exclusion zones are still enforced and the wreck continues to be monitored by the Maritime and Coastguard Agency.
Managing a Legacy: Proposals and Precautions
Over the decades, a variety of solutions have been considered for the Richard Montgomery. Options have ranged from full ordnance removal to structural reinforcement or burial in concrete. However, none have been pursued—primarily because the danger of disturbing the wreck is considered greater than leaving it alone.
The Maritime & Coastguard Agency, the Department for Transport, and the Ministry of Defence have stuck to a policy of passive containment. The site is clearly marked and monitored, with exclusion zones for shipping and—as of June 2025—a no‑fly zone prohibiting aircraft below 13,100 feet within a one‑nautical‑mile radius.
The remaining cargo, estimated at around 1,400 tons of high explosives including bombs of various sizes and white phosphorus smoke devices, remains buried in the forward holds beneath silt and collapsed steel. As long as the wreck remains undisturbed, the official assessment describes the threat as low, though not negligible.
While public imagination often oscillates between a catastrophic detonation and a safe cleanup, reality demands nuance. These wrecks are treated more like dormant geological faults—stable under current conditions but potentially volatile if tampered with.
Lessons from the Deep: The SS Kielce Case
A comparable cautionary example comes from the English Channel, with the Polish freighter SS Kielce. The Kielce sank in 1946, carrying munitions when it collided with another ship off Folkestone. The wreck settled in some 90 feet of water—well over twice the depth of the Richard Montgomery, which lies at approximately 50 feet.
In 1967, efforts to dismantle the Kielce ended badly. The Folkestone Salvage Company placed demolition charges on the hull and inadvertently detonated remaining munitions. The blast created a crater in the seabed over 150 feet long, 67 feet wide, and 20 feet deep. It registered as a magnitude 4.5 seismic event—detected across Europe and North America—and shattered windows and roofs in Folkestone, several miles away.
It is worth noting that despite its deeper waters and lower explosive payload, the Kielce explosion still caused significant damage. In contrast, the Richard Montgomery sits in shallower water—its masts still visible above the low tide—and holds far more ordnance. Its proximity to densely populated areas and strategic infrastructure such as Sheerness docks and Thames shipping lanes makes its situation uniquely sensitive.
The Kielce disaster remains a sobering historical precedent. It underlines the unpredictable dangers of attempting salvage operations on munitions-laden wrecks, and supports the reasoning behind official efforts to keep the Montgomery undisturbed.
Conclusion – Between Memory and Responsibility
The SS Richard Montgomery is more than a rusting wreck—it is a persistent testament to wartime legacies and the decisions we make to contain them. Its silhouetted masts serve as a stark reminder that beneath the Thames isn’t just history, but latent danger.
The Kielce incident teaches us that intervention—even cautious, professional intervention—can have unintended consequences. That wreck lay deeper and held fewer explosives than the Montgomery, yet when disturbed, its blast shook communities and created seismic ripples around the world.
The Thames wreck lies closer to shore, holding much more volatile material. It is not merely passive decay; it is a hazard managed by surveillance, exclusion zones, and measured restraint. While erosion and rust continue their slow work, the official approach remains surveillance—not removal.
In the end, the Richard Montgomery reveals much about our relationship with the past. It sits—watched, measured, contained—but unresolved. An explosive time capsule in shallow water, it tests the limits of prudence. As history recedes into memory, this wreck stands as a powerful symbol of the care and caution we must exercise in the aftermath of war.
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References
Daily Express. “Warning over UK ‘Time Bomb’ Ship Loaded with 1,400 Tons of Explosives.” Daily Express Online, June 2025.
Department for Transport. Annual Report on the Condition of the SS Richard Montgomery Wreck Site. London: UK Government Publications, 2022.
Kent Online. “New No-Fly Zone Introduced over Richard Montgomery Wreck.” KentOnline, June 4, 2025.
Maritime and Coastguard Agency. Wreck Monitoring Report: SS Richard Montgomery, 2023.
Smith, Roger. “The Kielce Explosion of 1967: Lessons from a Wartime Wreck.” Maritime Historical Review, Vol. 11, No. 2, 1998.
BBC News Archive. “Underwater Blast Rocks Channel: Wreck Detonates during Salvage.” BBC News, July 1967.
Folkestone Salvage Company Records. “Case File: SS Kielce,” National Archives Reference FS/1967/072.
