My Lords, in February last year City Airport was closed while a 500-kilogram unexploded World War II bomb was made safe. This short debate is about a much larger volume of unexploded and highly dangerous munitions that has been in shallow water in the Medway channel near Sheerness for 75 years. I am grateful to Professor David Alexander of University College London for briefing me extensively on this matter.
The SS “Richard Montgomery” was built in 1943 by the St Johns River Shipbuilding Company of Jacksonville, Florida, which built 82 Liberty ships for the US Government over three years. The emphasis was on speed rather than quality—after all, there was a war on—and the ships were regarded as expendable. Her construction time was just 137 days—not bad for a vessel 4.5 times the length of your Lordships’ Chamber. The hull plating was welded rather than riveted, so was more susceptible to cracking, and the low-grade steel used becomes brittle in the cold waters of the North Atlantic. The ships were not built to last, and indeed the SS “Richard Montgomery” did not. After several trips across the Atlantic, in August 1944 she was loaded with 6,225 tonnes of high-explosive bombs and detonators and arrived in the Thames estuary. The King’s harbourmaster—actually based in Southend—instructed her to moor at Sheerness middle sands in about 10 metres of water. This was unwise, as the vessel had a draught of 9.45 metres and a very full cargo.
Since then the wreck has remained essentially untouched, with its masts protruding above the surface, 2.4 kilometres from Sheerness and its population of 11,000. Three to five kilometres to the south-west is the Isle of Grain, with its oil-fired power station, four storage tanks for liquefied natural gas—each the size of the Royal Albert Hall—and another 18 oil storage tanks. It is situated less than 200 metres from a busy shipping lane.
So how much explosive remains on the wreck? In its most recent report, the Maritime and Coastguard Agency says there are 1,400 tonnes of explosives contained in the forward holds. However, this is in conflict with the ship’s original cargo manifest and the meticulous daily records of the salvage operation. These suggest that the vessel took on 35,943 individual explosive items, of which 13,961 remain. The salvage operation mainly removed the smaller bombs and shells, so those that remain packed on racks in the forward holds amount to slightly more than half the explosive weight of the original cargo—some 3,105 tonnes. This is more than double the figure quoted by the MCA. Can the Minister explain why there is such a discrepancy? Was the salvage operation much more effective than those who conducted it said at the time—this sounds inherently implausible—or have 1,700 tonnes of munitions been removed surreptitiously over the last 75 years without anyone noticing? Perhaps, as the state of the wreck has deteriorated, the bombs and shells have simply fallen out and are on the sea bed. That presumably means they are still in close proximity to the rest of the explosive cargo and remain as big a collective threat.
Certainly, some phosphorus has escaped from the munitions and risen to the surface of the water, where it has caught fire on contact with the atmosphere. At least 40 such instances were reported in one year alone. How often have such incidents been recorded in the past decade, and what threat do they pose to the rest of the cargo? My fundamental question to the Minister is: what is the state of the munitions that remain? How has that assessment been made? If an unexploded half-tonne bomb was still regarded as sufficient a threat to close City Airport last year, presumably these 1,400 tonnes of munitions on the MCA figures—let alone the 3,100 tonnes estimated from the manifest and the salvage records—are, by orders of magnitude, a far greater threat.
In 1970 the Royal Military College of Science prepared an assessment of what would happen if the entire remaining cargo were to explode: a 3,000 metre-high column of water and debris and a five metre-high tsunami. This would overwhelm Sheerness and the water wave, possibly carrying burning phosphorus, would reach the petrochemical installation on the Isle of Grain. Does the Minister accept the analysis of the Royal Military College of Science? If not, why not? Indeed, what is the current assessment of the effect of the entire cargo exploding?
A more recent risk assessment was conducted in 1999. I understand that it remains classified. Why? Are the conclusions so serious that the public cannot be told? Has the Minister read it and will she undertake to place a copy in the Library?
There are limited ways in and out of the Isles of Sheppey and Grain, either for the emergency services to converge in numbers and at speed or, for that matter, for people to evacuate. What contingency plans are in place to handle such an emergency and when were they last rehearsed? What is the assessment of the risk of a tidal wave travelling up the River Thames and reaching London? These are not circumstances in which the Thames Barrier, which takes up to 90 minutes to close, would be of much use.
Another worrying factor is the proximity of shipping. More than 5,000 vessels pass the wreck each year. Until 1978 there were 24 near misses, but later figures are not available. Perhaps this is because of two potentially catastrophic incidents in May 1980. In the first, the “MV Fletching” grazed one of the marker buoys and came within 15 metres of the wreck. Later that week the Danish-registered “Mare Altum”, a chemical tanker of almost 1,600 gross tonnage carrying low-flashpoint toluene, was on a collision course and disaster was averted only minutes before it would have hit the wreck. The consequences of that would have been unthinkable. How many near misses have there been in the period since then?
In 2017, a paddle-boarder posted a picture on social media of himself balanced on the wreck and pleasure boats often come close. In 1969, as a prank, students from Kent University phoned the police threatening to blow the wreck up. Not surprisingly, that led to a massive security operation. A similar operation was mounted during the 2012 Olympics, according to one source because a speedboat carrying three men and explosives was intercepted nearby. Was that security operation simply precautionary or was it in response to a specific threat? Indeed, what mitigations are in place to prevent a terrorist attack on the wreck?
The SS “Richard Montgomery” is owned by the United States Government. In 1948 and 1967, the US offered to make the wreck safe. Both offers were turned down. Why were those offers rejected? What were the last communications with the US on this matter and are the US Government still liable for the damage caused if the wreck explodes? As far as I am aware, every other wreck with such a dangerous cargo in the immediate waters around the British Isles has been made safe. Can the Minister confirm that this is the case and, if so, why has this wreck been left alone?
The Government’s policy appears to be to bury their head in the Sheerness sands, presumably in the hope that the problem will simply go away. Every year, however, the fabric of the wreck disintegrates further and, as surveys look at only its external condition, nothing is known about the contents and their condition. Any of the munitions found elsewhere on their own would immediately trigger a major evacuation and an emergency. So why are the Government so relaxed about thousands of such bombs and shells deteriorating together in an unstable environment, unguarded and unprotected? Why has nothing been done for 75 years? Why is there no plan to make the wreck safe? Perhaps the biggest question of all is: who will take responsibility for what happens if it all goes wrong?