Among historians, the defence of Great Britain in 1940 has been one of the most hotly debated topics of recent years. Since the end of the Second World War, the story of our finest hour has been resold countless times to meet an insatiable commercial demand for military history and nostalgia for our glorious past. The focus of this coverage, by the media at least, has been mostly pinned on the aerial conflict of the summer of 1940, which we now know as the Battle of Britain.


The courage, sacrifice and determination of the Battle of Britain pilots are all beyond question, but hypersensitivity to revisionism must not further detract from us recognising the centrality of the Royal Navy and Merchant Navy in the defence of Great Britain during this year.

The battle for Britain started in April 1940 as German troopships and the British Home Fleet converged upon Norway. Hitler was gambling that he could use the German Kriegsmarine (navy) to land his forces along the coast of neutral Norway in order to secure the coastal transport routes that took vital Swedish iron ore to Germany. Although the Royal Navy was more progressive than the other services in terms of intelligence appreciation, the Kriegsmarine held the naval intelligence initiative throughout 1940. Kriegsmarine signals could not be read and German knowledge of the disposition of British warships aided their landings. Initially misreading enemy intentions as a mass breakout of commerce raiders into the North Sea and Atlantic, the commander in chief, Admiral Sir Charles Forbes, finally realised a full scale German invasion was under way and ordered ships to Narvik, where two heavy defeats were inflicted on the Kriegsmarine.

Throughout the campaign, the numerical superiority of the Home Fleet and its allies was often offset by heavy German air support. “In the fjords, everything is to the bomb aimer’s advantage”, wrote one naval officer, referring to the fleet’s limited room for manoeuvre and the mountains screening enemy aircraft. Sailors came under murderous fire, but as Admiral Hamilton reported, the men were “very much shaken” at first “but after the first bomb salvo of near misses, their behaviour was all that could be desired”.

The Royal Navy had taken heavy but sustainable losses in the campaign, but the Kriegsmarine had lost around half of their ships including most of their destroyers. The damage to the rest of their fleet and the blockade of Trondheim also meant that no German capital ships would be available for an invasion of Britain in 1940. No wonder the Kriegsmarine’s commander in chief, Admiral Raeder, wrote “the losses… weighed heavily upon us for the rest of the war”. Churchill also wrote that after Norway, “…the German navy was no factor in the supreme issue of the invasion of Great Britain”.

The Kriegsmarine had lost half of their ships including most of their destroyers

German naval strength was so diminished by 26 May that Admiral Raeder’s chief of staff was forced to admit they would not be able to prevent the British Dunkirk evacuation of the British Expeditionary Force (BEF). So it was to prove. While RAF fighters were operating over Dunkirk, the Luftwaffe could not penetrate the Anglo-French defences, but as the RAF could not maintain a continuous presence, frequent and intensive raids were made on the harbour, beaches and ships. British ships came under their most intensive attacks on 29 May and 1 June, placing massive psychological strains on the crews. Again, much was to the bomb-aimer’s advantage, such as the ships’ limited room for manoeuvre and the lack of an established anti-aircraft defence around the harbour. Shipping also had to cope with heavy German artillery fire that successfully closed off one of the evacuation routes. Royal Navy losses were approximately 40 ships, including six destroyers, two of which succumbed to air attack, with 19 destroyers damaged.

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Nevertheless, around 338,000 troops were evacuated and the army was saved as a future deterrent to Hitler’s Operation Sealion, the planned invasion of Britain. Dunkirk also proved a major boost to British self-esteem and gave credibility to Churchill’s defiant ‘finest hour’ speech. The small civilian craft known as ‘The Little Ships’ played an invaluable role, including shuttling troops to the larger ships, but it must be remembered that around half the troops had been brought home in warships and most of the rest in ships manned by Royal Navy and Merchant Navy personnel.

Destroying oil stocks

As the BEF withdrew from the continent during May and June, the Royal Navy transported navy and army demolition parties to Europe with the object of destroying port facilities that might be used for an invasion and to destroy their oil stocks. These were the unpublicised Operations XD and XDA. Two million tons of oil was successfully denied to the Wehrmacht, and harbours including Zeebrugge were temporarily put out of action until November, with Calais and Boulogne unusable until September.

So important were these operations that the naval award list alone included two Distinguished Service Orders, two Distinguished Service Crosses, six Distinguished Service Medals with 11 others mentioned in despatches. Destroyers transporting these parties were subjected to heavy air attack and the sappers had sometimes exchanged fire with German troops. As Admiral Raeder acknowledged, the extensive damage to these harbours and their adjacent inland waterways precluded their immediate use as invasion ports and made the prospect of an immediate invasion impossible. Admiral Assman later told British naval intelligence: “We Germans could not simply swim over”.

By 4 June, Admiral Forbes was complaining about the diversion of destroyers and other smaller vessels from trade protection duties to home waters to await a German invasion. Both Forbes and Churchill were unconvinced that Germany had the capability to launch an invasion during the summer of 1940, with the prime minister hounding the first sea lord about the increase in merchant shipping losses, and attributing these to the diversion of resources to anti-invasion duties. “Anyhow, we cannot go on like this,” he wrote in August 1940. British, Allied and neutral shipping losses surged from 273, 219 gross tons in May 1940 to 571,496 tons in June, and would not fall back to the May figure during 1940. This was the beginning of the Battle of the Atlantic, and the first ‘happy time’ for German U-boats, in which more and more took full advantage of unprotected merchant ships, using good intelligence as well as new Brittany bases that allowed unprecedented access to the Atlantic supply lines. Churchill later admitted to worrying more about the Battle of the Atlantic than “the glorious air fight called the Battle of Britain”.

The early phase of the Battle of Britain also saw merchant shipping in the English Channel coming under heavy Luftwaffe attacks. “The Merchant Navy were the unsung heroes of the war,” remarked Spitfire veteran Jimmy Corbin, DFC, reflecting on the unpopularity of orders to protect these convoys. His commanding officer, Athol Forbes, had told the pilots: “These Merchant Navy boys have survived the U-boats lurking in the Atlantic to make sure you get fed, the least we can do is to afford them a little protection.”

Of course, it was not only food, but fuel for their aircraft being carried in these convoys. Sadly, these tributes were not echoed by everyone. Despite operating anti-aircraft guns, and having been the focus of merciless U-boat attacks, merchant seamen on leave from gruelling operations were sometimes given white feathers on the assumption they were dodging conscription. Outrageously, the merchant seamen were officially categorised as non-combatants and mostly lacked recognisable uniforms.

Admiral Assman later told British naval intelligence: 'We Germans could not simply swim over'

In July, the Royal Navy was charged with the odious but necessary task of removing any possibility of the French fleet falling into Axis hands – something that would have improved enemy invasion prospects enormously. Unable to obtain acceptable assurances from the French commander, Vice Admiral Somerville was obliged to sink the bulk of the French Mediterranean fleet at anchor with much loss of French life. A great burden of guilt was subsequently undertaken by the British but the affair had reassured Americans about the British determination to fight and almost certainly saved Churchill from being replaced as prime minister. American logistical support was absolutely crucial to continuing the war and American newspaper references to the Battle of Britain during June and July focussed very heavily upon these naval affairs. Americans viewed the Royal Navy as their traditional shield against foreign expansion and were concerned that it might end up in Hitler’s hands. Indeed, Anglo-American naval staff talks were now forming the basis of a growing transatlantic cooperation.

Despite its losses, the Royal Navy was still ten times larger than the Kriegsmarine. By September, the British defenders had four cruisers and 70 destroyers in home waters and could quickly call upon the heavy ships of the Home Fleet, now based at Rosyth. The Germans were now down to eight destroyers with no heavy ships immediately available for support. The British were not content to keep their ships in harbour as a mere passive deterrent and made a series of daring raids on enemy invasion ports in a variety of weather conditions. Smashing their way into Dunkirk, Boulogne, Calais and Ostend, British warships blew invasion barges out of the water with point blank gunfire night after night.

On 11 September, every port between Antwerp and Cherbourg was entered and shelled. In October, Cherbourg was bombarded along with Calais where the harbour sustained 45 salvoes of deadly plunging shell fire without the loss of any British warships. With German barge losses amounting to the equivalent of his reserves, Hitler ordered the dispersal of his armada to safer waters.

Disappointing results

The Air Ministry claimed that Bomber Command destroyed barges in September, and while they undoubtedly sank some, precision bombing was notoriously difficult in 1940. Churchill was unconvinced about the raids, writing “what struck me was the apparent inability of the bombers to hit these very large masses of barges.” The Air Ministry photograph showed disappointing results on rows of barges with just a few damaged at the entrance.

However, in order to build up the power of the RAF in Hitler’s mind, Raeder seems to have used ‘English bomber’ attacks as an excuse to have postponed a plan that neither he, nor the German naval staff wanted to implement. As Assman later wrote: “Naval staff also appreciated clearly that air supremacy alone could not provide permanent security against vastly superior enemy naval forces in the crossing area”. Even before the heavy bomber losses over London on 15 September supposedly brought about a postponement of the invasion, the Kriegsmarine war diary entry for 10 September already stated that the Luftwaffe was not doing enough to support Sealion. But the naval staff was not going to bother Hitler about it now because of expectations that the bombing would bring about a situation in which invasion would be unnecessary anyway. While no German military figure could state it explicitly at the time, the Germans had mentally given up on invasion before 15 September.

The British were not content to keep their ships in harbour as a mere passive deterrent

So the Royal Navy decimated the German surface fleet at Norway, saved the army at Dunkirk (and other locations), disabled key invasion harbours, sank barges and gave the Americans good reason to continue their essential logistical support. Its actions saved Churchill's premiership and struck fear into the German invasion planners. But it cost the lives of many sailors. For example, the battle in which the carrier Glorious was sunk in the Norwegian Sea in June 1940 cost 1,474 navy lives.

In keeping the Atlantic lifeline afloat, the Merchant Navy sustained 1,730 killed during the period of the Battle of Britain – 10 July to 31 October 1940. Compare this with 537 from Fighter Command and around 957 from other RAF commands killed in action for this period. In terms of human sacrifice, the figures speak for themselves but attention is concentrated on the fighter boys whenever ‘finest hour’ is uttered.

Churchill's 'Battle of Britain' phrase was also hijacked by the British propaganda machine in 1940, and was defined by an Anglo-American media-construct to mean the air battle that prevented invasion. In contrast, by late 1940 the Admiralty was defending itself from ill-informed criticism for its handling of the early naval campaigns and the loss of some major warships. But if the Battle of Britain must remain exclusively and indelibly linked with the fighter defence of 1940, then surely the time has come for a Finest Hour Monument to honour the broader Battle for Britain participants?

Anthony Cumming is the author of The Royal Navy and the Battle of Britain (Naval Institute Press in September 2010)

Timeline: The naval war of 1940

April–May 1940

Allied and German naval forces clash around Norway. The Allies lose the land campaign but the Kriegsmarine has been decimated with the loss of three cruisers, one gunnery training ship, eight U-boats, one torpedo boat and ten destroyers plus various support craft. The Allied naval losses are also heavy but more sustainable.

May–June 1940

The Royal Navy and Merchant Navy save the British Expeditionary Force from certain destruction at Dunkirk but sustain heavy shipping losses. All the BEF's heavy equipment is lost but the troops will provide the nucleus of home defence.

May–June 1940

Operations XD and XDA are carried out by navy and army demolition parties. They deny the Germans the immediate use of most invasion ports along the continental coastline and destroy their oil stocks. The operations are improvised and conducted in great secrecy but many sailors and soldiers will receive military decorations.

June 1940

215,000 troops are rescued from western France in Operation Ariel. The sinking of the troopship RMS Lancastria with the loss of at least 3,000 lives is one of the bloodiest disasters of the war. The Royal Navy is still ten times larger than the Kriegsmarine.

July 1940

Churchill orders the destruction of the French fleet at Oran if they do not put themselves beyond Hitler's reach. The ruthless naval bombardment sours Anglo-French relations but reassures Americans about the British determination to fight. Churchill, who has suffered internal opposition from the Conservatives, consolidates his position as prime minister.

July 1940

U-boats operating from French ports now begin their first 'happy-time'. Losses will start to fall in November 1940 when the Royal Navy release escorts from anti-invasion duties, but the situation remains critical into 1941. The Merchant Navy will sustain heavier proportional casualties than any other service during the war.

September 1940

Invasion ports along the enemy coast are raided by the Royal Navy and, with the assistance of RAF Bomber Command, invasion barges equivalent to the German reserves are sunk. Hitler begins limited dispersal of the barges from 19 September with further dispersal from 12 October.

September 1940

The Destroyers for Bases deal is announced between Britain and the USA followed by a British pledge never to sink or surrender their fleet. Fifty old (but needed) destroyers are exchanged for British Caribbean naval bases. This paves the way for further aid, including the Lend-Lease Bill of March 1941.


This article was first published in the April 2010 issue of BBC History Magazine