HMNB Devonport: The Dockyard the Admiralty Once Called Unsafe for Nuclear Submarines

Built to Watch France, Not Holland

Devonport began life as Plymouth Dock, established after the Glorious Revolution of 1688 shifted Britain's strategic anxieties away from the Dutch and firmly onto France, whose Atlantic ports at Brest and Cherbourg made a naval base further west than Portsmouth a genuine priority. Edmund Dummer, the Navy's Surveyor, surveyed the West Country and a contract was let on 30 December 1690 to build a dockyard on the Hamoaze, the tidal reach of the River Tamar, with work beginning the following year.

Dummer's dry dock there is generally credited as the first successful stepped stone dry dock in Europe, using stone rather than timber to reduce fire risk, and the site's deep, sheltered water and western position let the fleet blockade French Channel ports considerably more efficiently than Portsmouth ever could.

A Dock That Outgrew Its Town

The yard expanded steadily through the eighteenth century, adding a second dock in 1727, a third in 1762 and a fourth in 1793, and by 1801 the surrounding settlement had actually outgrown its parent town, with Plymouth Dock's population of 23,000 exceeding Plymouth's own 19,000. This rather unusual state of affairs was formally recognised in 1824, when the town was renamed Devonport by royal decree, with the dockyard itself following suit and formally becoming HM Dockyard, Devonport a couple of decades later.

Further major expansion came with the Steam Yard at Keyham, built between 1844 and 1853, and the substantial Keyham Extension, which opened in 1907, together making Devonport the largest naval dockyard in Western Europe, a claim still commonly repeated today, though it is worth noting that some more recent comparisons suggest the French naval base at Toulon may now rival or exceed it in raw area, even if it falls well short of Devonport's historic pedigree.

Fire, Shipbuilding, and a Very Long Blitz

A major fire tore through the yard on 27 September 1840, an event significant enough to be recorded in contemporary paintings now held by the Royal Collection Trust, while the twentieth century saw Devonport building a long succession of submarines, from J, K and L-class boats in the First World War through to T-class and Amphion-class vessels, with HMS Scylla in 1971 standing as the very last ship ever built there after some two hundred and eighty years of continuous shipbuilding.

The city around the dockyard paid a heavy price during the Second World War. Plymouth suffered fifty-nine separate air raids between July 1940 and April 1941 alone, killing 1,172 civilians and injuring a further 4,448, and while the dockyard itself continued operating throughout, the surrounding South Yard sustained very serious damage, with some accounts putting the proportion of destroyed or damaged buildings there as high as eighty-five per cent by the end of 1942, though this specific figure could not be independently corroborated beyond a single source and should be treated with appropriate caution rather than repeated as settled fact.

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Ruled Unsafe, Then Given the Bomb Anyway

Devonport's path into the nuclear age contains a remarkably striking twist. In 1964 a government safety committee chaired by Solly Zuckerman actually rejected Devonport as unsuitable for nuclear submarine refitting work, citing wind and population risk concerns, yet barely five years later, in 1969, the government confirmed Devonport as the country's third nuclear dockyard regardless.

The purpose-built Submarine Refit Complex, complete with an eighty-ton crane specifically designed for lifting reactor components, opened between 1977 and 1981 and was formally opened by Prince Charles in May 1980, and by 1993 Devonport had become the single site handling refits for every class of Royal Navy submarine, including the Vanguard-class deterrent boats, a role it retained as the sole nuclear submarine refitting and refuelling base in the country from 2002 onward.

It is worth being precise here, since submarine home-porting and submarine refitting are two different things: while operational basing of the submarine fleet has consolidated at Faslane, with the last Trafalgar-class boat, HMS Triumph, making her final home-porting voyage there before returning to Devonport for decommissioning in December 2024, Devonport itself has not simply become a surface-ship-only base, and continues to carry out the Navy's heaviest submarine maintenance, dry-docking and dismantling work, including periodic major work on Faslane-based Astute-class boats.

Less happily, a considerable backlog of decommissioned nuclear submarines, a dozen or more at recent count, remain laid up afloat at Devonport awaiting full defuelling and disposal, a situation a 2018 parliamentary committee report described bluntly as not fit for purpose, though a subsequent contract with Babcock has since begun addressing the backlog in earnest.

Still One of the Big Three

Today HMNB Devonport remains one of the Royal Navy's three main operating bases alongside Portsmouth and Faslane, covering more than six hundred and fifty acres with fifteen dry docks, twenty-five tidal berths and five basins, and it is home to the Navy's amphibious ships, survey vessels and the majority of the Type 23 frigate fleet, with every future Type 26 frigate already confirmed to be based there. The site has been managed by Babcock International since 2007, which also owns the freehold of much of the North Yard, and the base continues to support several hundred local firms and a meaningful share of the whole Plymouth economy, a remarkable legacy for a dockyard whose very first commission, back in 1690, was to build a modest seventy-three-ton vessel called the Postboy.

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