World War II: How barrage balloons defended against the Blitz
How did wartime London try to shield itself from Nazi bombs? Barrage balloons were surprisingly effective defences. Here’s how they foiled the Luftwaffe.
Image: Barrage balloons are seen in images from D-Day, but they also played an important role in defending London during the Blitz | Public Domain
One of the best-known chapters of World War II is ‘the Blitz’, when the Luftwaffe subjected British cities to eight months of sustained bombing. It was a change of aerial strategy for Nazi Germany after its defeat in the Battle of Britain.
However, during both this 1940 tussle and the lengthier bombing campaign that followed, the British people took comfort from the nation’s resilient defences. These included barrage balloons, known to have struck fear in the hearts of German pilots.
Watching World War II with Tom Hanks will bring home how terrifying the Blitz period really was. Still, you will also get a strong sense of how the famed ‘Blitz spirit’ took shape. We at Sky HISTORY see barrage balloons as an underrated part of that equation.
What were barrage balloons?
If you’ve seen photos of wartime London, you have probably already caught sight of barrage balloons. As far as balloons go, they look pretty big even in photos. Those used in Britain during World War II were reportedly ‘three times the size of a cricket pitch’.
Though shaped like blimps or zeppelins, they were not engine-powered. They were filled with hydrogen, which enabled them to be floated as high as 5,000 feet in the sky. A long steel cable running from the balloon would tether it to a concrete block or a vehicle. Operators on the ground could use a winch to adjust the balloon’s altitude.
An unusual test at the Tower of London
World War II certainly wasn’t Britain’s first experience with using barrage balloons in warfare. We had already had plenty of practice during World War I about two decades prior, when they caused a lot of trouble for German pilots.
So, in the late 1930s, when Europe appeared to be sliding back towards war, it made sense to turn to barrage balloons once again. The Royal Air Force (RAF) even tested one in the Tower of London’s dry moat on 8th October 1938.
Large crowds of spectators gathered to watch the spectacle. Though the balloon was removed from the moat after just two days, the test was deemed a success. In November, the RAF formed a new arm, Balloon Command, that would be trusted with deploying barrage balloons across the UK should war break out.
How did the RAF use barrage balloons?
In September 1939, Germany invaded Poland, igniting the beginning of World War II in Europe. The UK government took precautions to protect its citizens, including evacuating children to the countryside. However, the still highly populous London remained an irresistible target for Nazi bombers.
By the summer of 1940, nearly 1,500 barrage balloons were in operation nationwide. Of these, about a third were in the London skies. The Blitz began the following September.
As early as 20th September 1939, the Tower of London’s moat had a barrage balloon again. It was raised and lowered mostly by men from the Auxiliary Air Force, as became standard practice with other balloons across the capital.
As time went on, though, there was pressure to send more and more of these men to fight overseas. So, who would hold the fort (or, to be more exact, the balloons’ winches) on the home front? The job mainly fell to women, despite previous (and soon to be disproven) concerns that they would not be capable.
What made barrage balloons effective?
The presence of barrage balloons would often force Luftwaffe pilots to fly higher than 5,000 feet to avoid them. However, this would make bombing targets harder to hit, not to mention put the planes in range of anti-aircraft guns. German planes flying lower to the ground would be in danger of taking damage from the balloons’ cables.
Nazi bombers could deliberately attack the balloons instead, but doing so at too close range posed its own problem. These inflatables contained hydrogen, a highly flammable gas. So, attempts to destroy the balloons could set off large explosions that would engulf the assailing aircraft, too.
Barrage balloons ceased to be such a common sight in London after the Blitz came to an end in May 1941. Nonetheless, they were resurrected a few years later, when they were found to be effective against the German V-1 bombs sent over the English Channel.
The use of barrage balloons was phased out after the war, when newer, more advanced technologies rendered them redundant.
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