These inventions may look like they’re straight out of a sci-fi film, but in fact these are real designs that were developed in a British war lab over 70 years ago. Ministry of Defence 1, also known as ‘Churchill’s Toyshop’, was a top-secret weapons laboratory set up in 1939 by Winston Churchill – a firm believer in the importance of science and technology in warfare. He encouraged his scientists to trial even the most absurd of inventions – many of which never made it beyond the drawing board – but some were so successful that they played a vital role in ending World War II.

1. The Panjandrum: A giant wheel covered in rockets

The Atlantic Wall was a series of robust fortifications built after 1942 by the Nazis to defend against an anticipated Allied invasion. It posed a significant obstacle for Allies, and so a potential solution to create a breach large enough to allow a vehicle through was dreamed up by one of Churchill’s military think-tanks.

The Panjandrum was an unlikely-looking weapon, made up of two large wooden cartwheels with a ton of explosives sandwiched between them inside the axle. Cordite rockets were to propel it at predicted speeds of up to 97 kilometres (60 miles) per hour, which even without the deadly force of the explosives it carried, was pretty terrifying considering it weighed around 1,800 kilograms (4,000 pounds).

After extensive trials, the prototype had a disastrous final test in which it veered dangerously off course and disintegrated in the sea. It was promptly canned.

2. The Time Pencil: A hidden detonator with sights on the Fuhrer

Otherwise known as ‘pencil detonators’ or officially as ‘Switch, Number 10, Delay’, these were pencil-shaped timed fuses with a vial of corrosive copper chloride at one end. To activate it, the vial was crushed so the copper chloride would begin to dissolve a metal wire. Once the wire snapped, it released a spring that propelled a striker down the hollow tube to the percussion cap, to detonate the explosives it had been inserted into.

These were used extensively during covert operations by the SAS in Africa. One of these detonators was used in the 20 July plot of 1944, in the briefcase-bomb attempt to kill Hitler.

3. The Limpet Mine: Like a sea mine, but with a man attached

The idea of using a human torpedo to attach explosive charges had been around since the end of World War I. Churchill’s version was attached by frogmen who used the most powerful magnet in the world at the time to attach around two kilograms (4.5 pounds) of explosive to an enemy ship, capable of punching a large hole in the hull.

They were used in the war to devestating effect. Seven Japanese ships were sunk or disabled by Allied commandos alone, using limpet mines in Singapore Harbour, 1943.

4. Project Habbakuk: A giant iceberg aircraft carrier

Steel and aluminium were at a premium during the war, so when inventor Geoffrey Pyke, who worked at Combined Operation Headquarters (COHQ), was considering a way of protecting Atlantic convoys beyond the reach of aircraft cover, he realised the answer was ice: huge flotillas carved out of icebergs that could house aircraft and provide a runway.

The problem was that icebergs tend to roll over, so Pyke’s answer was a combination of wood pulp and ice, which he called ‘pykrete’. This wouldn’t sink, was much stronger than ice and wouldn’t shatter, so it could easily be carved into shape. However, it never came into being. Pyke encountered a series of engineering problems that ultimately required the use of some steel in Habbakuk. Plus, the invention of long-range aircraft fuel tanks and the use of airfields in the Azores made it redundant.

5. The Sticky Bomb: A deadly explosive you (sometimes) can’t outrun

This was was a kind of grenade consisting of a glass sphere filled with over half a kilogram (around 1.5 pounds) of nitroglycerine, covered with an extremely sticky adhesive and encased in metal.

Its handle contained a five-second fuse and a safety pin that, upon being pulled, released the metal casing and exposed the adhesive. In theory, the sticky bomb could be attached to a passing tank, although in practice tanks often proved too dirty or wet for the bombs to stick. Despite this, 2.5 million were made and used between 1940 and 1943.

6. Artificial Harbours: A pop-up invasion aid to bring the tanks ashore

‘Mulberries’, or artifical harbours as they were otherwise known, were portable, temporary harbours designed specifically in World War II to help the Allies unload the heavy cargoes associated with a large-scale invasion.

In the years leading up to the D-Day landings, it had become apparent that any attempt to land en masse on the Atlantic coastline of Western Europe would require the use of the French harbours. And to do that, the Allies would need to depend on penetrating the Nazi Atlantic Wall, which could not be done. Instead, the Mulberries were to be transported and assembled off the French coast, providing mobile port facilities including cranes, roads and piers.

‘Mulberry A’ and ‘Mulberry B’ were successfully used for the invasion of Normandy in June 1944. The American Mulberry A was destroyed by storms but the British Mulberry B served for six months after D-Day before being decommissioned.

7. The PIAT: A one-man artillery barrage (when it hit anything)

By the middle of World War II enemy tanks had become increasingly well armoured, to the point that they were impenetrable to the outdated infantry grenade launchers. The Projector, Infantry, Anti-Tank (PIAT) was a portable mortar system that used a powerful spring to arm and launch a 1.1-kilogram (2.5-pound) bomb with a shaped charge up to 110 metres (360 feet) away.

They were first issued to British forces in 1943 and used throughout the war by the Allies. Although not entirely reliable, they were quite capable of taking out enemy tanks when they hit their targets and detonated.

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