“Blue Peacock”, the atomic land mine with a hidden secret.

A look at the strange history of Britain’s Blue Peacock atom bomb land mine project from the 1950s.

13 min readMar 22, 2022

In the light of developments in Ukraine and Vladimir Putin’s frequent reminders that he has nukes, we’ll be hearing a lot of how Russia’s doctrine includes the use of tactical nuclear weapons. These are things like nuclear artillery shells, used for limited objectives, such as wiping out an armoured column that’s in your way. Why, the tactician asks, should I deal with a line of tanks one at a time when you can destroy all of them at once? Obviously, this assumes that you’re upwind of the detonation and not overly worried about using any of the land that gets contaminated with radiation for the next few hundred years.

Whilst the Russian’s doctrine is reasonably well known, you’ll be hearing very little about the West’s views on tactical nuclear weapons. This silence was because, for most of the Cold War, the main threat was a Russian invasion of Western Europe, and it was politically awkward to be destroying one’s allies whilst “protecting” them. Unsurprisingly, the West German public and politicians tended to have strong views about a nuclear exchange taking place on their land.

But for was a brief, magical, period in the 1950s, there was no need to consider public opinion, because Germany was still in the doghouse (hundehaus in German) on account of their enthusiastic participation on the losing side of World War 2. This meant that the Western allies were able to consider the use of small yield tactical nuclear weapons to address the main issue of the day; how to stop the numerically superior Russian army as it swept westwards should they decide to invade?

In the mid-1950s, Britain was already basking in the radioactive glow of getting its first atom bomb into service under the codename of Blue Danube (also known as the Special Bomb, Smallboy and the imaginative Mark1 Atom Bomb). The Blue Danube was a Plutonium/Uranium 235 implosion warhead, designed to be dropped from the air by Britain’s V-Bomber force. With a yield of 10–12 kilotons, it was a little less powerful than the Little Boy bomb dropped on Hiroshima in 1945.

Mushroom cloud from a Blue Danube bomb dropped from an RAF Valiant B1 at the Maralinga test site in Australia. Those poor kangaroos.

No doubt a bigger bang would have been preferred but the scarcity of the active ingredients, led to a “quantity over quality” decision. The British decided to manufacture up to 800 of the rudimentary weapons and took delivery of their first operational bomb in 1953, a full year ahead of the delivery of the bombers needed to drop the device. This meant that the newest and most powerful bomb in the British arsenal was effectively targeted at RAF Wittering, near Peterborough, instead of the Russians. But, apart from the vexed issue of delivering the weapon, the Blue Danube device had much going for it; it was British, it would work most of the time, and it was ready to be used in innovative ways.

When challenged with halting a Russian invasion, British boffins turned their considerable talents to the exciting new concept of nuclear land mines. After all, what could be more innovative than hiding atom bombs in the German countryside for the unsuspecting Ivans to stumble across?

Conventional land mines were proven defensive weapons, capable of blowing up a tank, and sea mines had always been popular with everyone apart from sailors, so why not bury a few atom bombs in the path of an invading army and see if that worked? The boffins reasoned that the massive bang would destroy at least some of the Soviet horde as it swept westwards. The fact that the weapon would irradiate a large tract of land, rendering it useless to the conquering communists, was just a bonus.

It’s unclear who first came up with the idea of the nuclear land mine but at the time there was a general enthusiasm for all things atomic and a marked trend for shoving atomic devices into pretty much anything that existed. I have a vague suspicion that plans for an atomic toaster will emerge at some stage.

What we do know is that a British army policy paper stated that, “A skilfully sited atomic mine would not only destroy facilities and installations over a large area, but would deny occupation of the area to an enemy for an appreciable time due to contamination.”

The plan was to deny strategic infrastructure to the invaders, perhaps demolishing areas with oil refineries, heavy industry, or key points in rail and canal networks. The atom bombs would be buried in the likely path of an invasion and would be detonated when an unsuspecting Soviet Bloc tank division wandered too close. And so, with the theory all worked out, the boffins at the Atomic Weapons Research Establishment picked up their pencils and got to work.

It seems at this point that Churchill’s wartime directive that operational codenames should be suitably martial, or at least not silly, had either worn off or didn’t apply to weapons development projects. During the dark days of the war, Churchill had been understandably sensitive that he was in the business of sending many young men to fight in operations from which they might not return. Mindful of the letters that would be written to grieving next of kin and ever mindful of history’s verdict, he issued an edict that silly, cute, and fun names were not to be used for activities that were neither silly, cute, or fun.

It seems the memo didn’t get through to the Atomic Weapons Establishment where Britain’s atom bombs were being invented, improved, and manufactured. The land mine project duly began under the name Brown Bunny, managing to hit the trifecta of being silly, cute, and fun all at the same time. Luckily, wiser councils prevailed, and the project was renamed [checks notes] Blue Bunny. This new name, which presumably made it past the committee stage, had the advantage of being in line with the “Blue” codenames that were in use for a series of atom bomb weapons, such as Blue Slug, Blue Water and the aforementioned Blue Danube, but still failed the silly, cute and fun test.

Luckily the Blue Bunny atomic landmine was never used in anger, preserving its unsullied codename for the exclusive use of the Blue Bunny Ice Cream company. At this stage my legal advisors would like me to clarify that ice cream manufacturers are entitled to have a silly, cute and fun brand name and are in no way associated with destructive power of a 10 kiloton atom bomb.

Meanwhile, back at the drawing board the designers were wrestling with the job in hand, namely, how to repurpose the Blue Danube atom bomb into the Blue Bunny atomic land mine? There were a few problems and design issues to resolve; the Blue Danube physics package wasn’t the most reliable, the land mine needed to be portable, it needed to be waterproof when buried underground, it needed to go bang when it was desirable to do so and not go bang when a large mushroom cloud of radioactive debris was not needed.

The reliability of the Blue Danube atom bomb was caused by two main problems. Firstly, let’s remember that this was the early days of the British atom bomb programme, and many things were still held together with string and chewing gum, or at least they would have been except the Yanks were the only ones with gum in those days.

The fissile materials needed, that’s the radioactive stuff that makes an atom bomb fizz, were scarce and so the British were leaning towards churning out lots of lower yield bombs rather than time-consumingly concentrating materials into fewer big bombs. The logic was clear; in World War 2, the British had proved they could deliver large number of bombs, roughly on target, so the approach made sense. To achieve this end, however, they needed those 800 bombs to enter operational service as soon as possible. This meant that Blue Danube needed to be mass-produced at a time when, developmentally, it was little more than a glorified physics experiment that lived inside a laboratory. To make it look more warlike, the whole apparatus was popped inside a metal case with fins on it so it would drop out of a bomber smoothly. If you want a mental image about what a Blue Danube bomb looks like, just imagine a bomb from a 1960s cartoon and a wily coyote clinging to the casing.

Another issue lay with the unreliable lead-acid accumulators that acted as the electrical power source needed to get the fission chain reaction started; a problem that would only be solved in later iterations. To cut a long story short, the Blue Danube might go bang, or it might not. Not a problem if you are sending several planes towards the target and have a bit of redundancy built in, but if you are burying one atomic mine in a strategic location, you have just one shot and you kind of want it to work. Work continued to make the device more reliable throughout the Blue Danube’s operational life.

Another problem faced with the land-based weapon was how to protect the delicate innards from water. If you’re dropping a bomb from the air, a little light rain is unlikely to cause much problem during the short time it’s exposed to the elements. However, if you’ve got to stick your bomb under the soil in a field with a low water table, there’s a good chance that your state-of-the-art weapon may start to ship a little water, wreaking havoc on your delicate electrical firing mechanism. This problem was solved by encasing the whole shebang inside a large waterproof metal cannister. Of course, this needed to be tested so they carted the casing off to a large, flooded gravel pit in Sussex and pushed it under the water to check for leaks. In case any inquisitive locals asked why the military-types were bothering the ducks, the plan was to explain that they were testing a large insulated waterproof container, which, I guess, they were. If further questions were forthcoming the cover story was that this was indeed a case for a nuclear device, but it was an atomic power unit for the army.

The other main design problem facing the boffins was how to make the mine go off at the right time? Traditional land mines might be scattered about liberally waiting for an unsuspecting soldier or tank to set off a pressure sensor, but with a large metal cylinder buried underground, something a little more creative was required. Not only was it important to be confident that it would detonate when desired, it also had to be protected so it wouldn’t be deactivated by unfriendly forces who stumbled across it or were tipped off by a concerned farmer keen to avoid incineration.

As we all know, atom bombs are designed to go bang, but how do you make them go bang at exactly the right moment? This was an especially vexed question when you consider that it would have to be exploded under the unsuspecting noses of an armoured division advancing with murderous intent. Obviously, given the size of the expected explosion, a remote mechanism was preferable. It was decided that the lucky British soldier who had the honour of setting off the mine would be able to trigger the device from 3 miles away by pressing a button at the end of a very long wire. Here, our fictional squaddie would be safe from the worst of the blast radius and, presumably, would do his best to stay upwind of the resulting cloud of radioactive material falling from the sky.

So far, so good, but what if our poor British soldier was overrun by the Russian hordes before he had a chance to detonate his atom bomb mine? The answer to this conundrum was to prepare a trap; the mine was designed with a clockwork timer set to explode after 8 days, allowing the device to be left behind to provide an unpleasant surprise even if the British were busy re-enacting the evacuation at Dunkirk. Once primed, the bomb literally became a ticking time bomb. Presumably, the scenario where the Russians were forced back over the border and, in the confusion, the mine scored a massive own goal was considered too outlandish.

Having covered the optimistic intentional explosion and the pessimistic “dead hand” military disaster scenarios, the boffins turned their ingenuity to a more likely events; what if the Soviet Bloc forces found the bomb and attempted to defuse it? For this scenario, an unpleasant surprise was prepared for the bomb disposal squadski; the device equipped with motion sensors that were designed to trigger the device if they were tickled a little too much.

Similarly, the device would go bang if anyone attempted to fill the casing with water in an attempt to short circuit the delicate electronics inside. Finally, in a nod towards the perceived technical finesse up the average Russian soldier, the bomb was designed to go off if the casing was pierced by gunfire. Let’s just pause at this moment and tip our hats to the gutsiest bomb disposal expert in Europe who, when confronted with a large ticking, radioactive canister, might decide that the right tool for the job is a heavy calibre machine gun. In each of these scenarios, a generous ten seconds would elapse before everything in the area was vapourised.

With detonation assured, the next problem was delivery. As mentioned before, the Blue Danube bomb was designed to be dropped from Britain’s V-Bomber fleet. Weighing in a 7 ½ tonnes, the bombs was essentially a large cylinder. All very well and good until you needed to drag it out onto a bit of secluded farmland. Whilst the dropping mechanism for the bombers had benefitted from years of development, the plan for the Blue Peacock featured a certain rustic simplicity; the device would be loaded onto a large truck and driven off into the countryside.

One by one the development problems were overcome.

It was about this stage that it emerged that the Blue Bunny codename wasn’t as secret as hoped and rather than risk being mocked by the Russians, the name was changed to the immeasurably more macho “Blue Peacock”. To the relief of project administrators and future ice cream manufacturers, at this point the designers stopped messing about with the name and turned their minds and turned their mind to the final question at hand…

As our friends at Blue Bunny Ice Cream know, an ice cream that gets too warm fails to behave as an ice cream should. Some things are sensitive to temperature, and it turns out that an atom bomb warhead that gets too cold might also fail to behave as a bomb should. Whilst the ice cream industry relied on the introduction of reliable freezers to deliver their product, the atom bomb industry had the opposite problem.

It had been observed that the German border can get a bit chilly in winter and there was a very good chance that the atomic land mine’s innards might freeze, rendering it as little more than a large radioactive garden ornament until the weather warmed up. Sadly, the Russians couldn’t be relied on to attack only in the warmer months, as both Napoleon and Hitler would have testified had they been around in the 1950s. So, the problem remained, how to keep the Blue Bunny from freezing?

Obviously, it was a little too much to expect your average West German farmer not to be curious when asked if he’d mind running an extension lead from his farmhouse to an electric heater. Stuffing the bomb with insulation was also considered, but where was the fun in that? Finally, the boffins hit upon the perfect mix ingenuity, impracticality, with just a sprinkling of eccentricity thrown in; why not heat the underground atom bomb with live chickens?

The idea was to pop a few chickens, with sufficient food and water, into the casing and use their combined body temperature to keep the mechanism above freezing point. As I understand it, the chickens thought this was a dumb idea and, luckily for them, so did someone else on the project team; the idea was never developed operationally.

The whole idea was so far-fetched that when details emerged on the 1st April 2004 (coinciding with April Fool’s Day, the traditional day for playing pranks in the UK) the BBC checked with the National Archives whether this was actually a joke. They were informed that “The Civil Service does not make jokes.”

Two prototypes of the Blue Peacock land mine were developed, but the main project was cancelled in 1957. Obviously, it would be nice to assume that the project was canned because it was unethical to be burying atom bombs under your ally’s farmland, or even that the project was cancelled in a fit of embarrassment following the chicken incident, but sadly it was not. The reality was that the Blue Danube warhead just wasn’t reliable or portable enough for general use. The final nail in the coffin for Blue Peacock was the realisation that the unwieldy 7 ½ tonnes cylinder, once loaded onto a truck, tended to be rather top heavy when driven off road in exactly the conditions that would be encountered in wartime.

In 1957 the project was cancelled as newer, better, and more horrifying weapons were developed, consigning the Blue Peacock device to the dustbin of history. However, it seems that someone loved this project enough to preserve one of the prototypes, which is now held in the Atomic Weapons Research Establishment museum. Over time, documents about the project and the rest of Britain’s early atom bomb programme have emerged, but many documents remain a secret. One wonders what other weird and wonderful ideas exist in those secret papers…

One thing is certain, whatever secrets still exist, they are unlikely to be weirder than the story of the poultry-powered plutonium-packing atomic land mine.

If you enjoyed this sideways look at the Blue Peacock project, make sure you click follow. If you’re not a Medium member consider signing up for membership using this link. You’ll get get unlimited access to all the stories on the platform as well as all the articles I put on here.

If you do I’ll get a small commission as a thank you from Medium.









I’m interested in lots of things and write about them. History, nature, environment, business topics, experimental stories and anything else I fancy.