The history of Britain's nuclear weapons

This is the first atomic bomb successfully tested by the UK in 1952, making Britain the third nuclear power in the world, and to this day it maintains its nuclear arsenal. But in fact, Britain was one of the first countries involved in the development of atomic bombs. They began research on nuclear weapons as early as 1940.

A scientific group, known as the MAUD Committee, was established in 1940 to determine the feasibility of using nuclear fission to create an atomic bomb. The following year, the Committee produced a report which demonstrated that this was indeed possible. The so-called Tube Alloys programme was set up to develop the idea - however, Britain did not have the resources, equipment, or materials to do this alone, and the country was under attack from German bombing. After lengthy negotiations, Britain signed an agreement with the United States in 1943 to share all nuclear research and development with each other and Tube Alloys was merged with America’s existing programme, the Manhattan Project.

Their first successful nuclear test on 16 July 1945 ushered in the nuclear age. Less than a month later, atomic bombs were dropped over Hiroshima and Nagasaki. The devastation revealed that Britain and the United States had created a weapon of unparalleled destructive power.

With the end of the Second World War, the former allies of the US and the Soviet Union now found themselves opposed along ideological lines. The United States had shown the Soviet Union their hand by releasing their superweapon and fear was growing that Soviet scientists would soon develop their own.

To try to prevent Soviet spies from obtaining information relating to nuclear technology, the United States introduced the Atomic Energy Act (also known as the McMahon Act in 1946 which severed ties with Britain and would transfer all nuclear development into civilian, not military, hands.

Britain now needed to make a choice: take a step back and allow the United States to cement itself as the only western nuclear power or develop its own atomic bomb to stand as an aggressor on the world stage. Britain chose the latter and set to work under the name High Explosive Research.

Despite post-war reconstruction being at the forefront of British people’s minds – it’s worth noting here that rationing did not end until the early 1950s – High Explosive Research was seen as a Labour government priority, especially once the Soviet Union successfully tested their own atomic bomb in 1949.

Although British scientists had been involved with the Manhattan Project, they still did not have all the required knowledge to make an atomic bomb. Nevertheless, within just a few years they did successfully develop their own.

Churchill came back into power in 1951 and the UK had plans to test its first weapon – a 25-kiloton plutonium implosion bomb.

The uninhabited Montebello Islands, located around 80 miles off the coast of Australia, were chosen as the test site and the project was named Operation Hurricane. Australia agreed to allow Britain to use the islands – hoping that their willingness to help might lead to the supply of nuclear energy for its population.

On 3 October 1952, the first atomic bomb was detonated on board the ship HMS Plym which was moored in a lagoon on the islands. The impact of the explosion left a crater 6 metres deep and 300 metres wide on the seabed. With this successful test, Britain had secured a place at the top table with the other nuclear superpowers, but Operation Hurricane had come at a cost: an estimated £150 million, billions of pounds in today’s money.

But the impact of the test, and successive tests throughout the 1950s, was not just financial.

In the mid-1980s, the McClelland Royal Commission found that nuclear fallout had serious and long-lasting effects on those involved in the testing and the indigenous populations in Australia.  The British and Australian governments have paid some compensation to those effected, but discussions remain live, and investigations are ongoing.

Nuclear warfare presented new technological challenges; jet bombers were needed to carry and deliver heavy nuclear weapons at long-range, high altitudes and speed. This led to the development of the V-bombers, consisting of the Valiant, the Vulcan and the Victor.

V-bomber bomb bays were designed to carry a free-fall bomb called Blue Danube, the first UK-built nuclear deterrent. A Vickers Valiant painted in anti-flash white, which was thought to protect the aircraft and its crew from thermal radiation, successfully released the weapon on 11 October 1956 and became the first RAF aircraft to drop an atomic bomb.

From 1962 to 1969, Britain’s primary nuclear deterrent was the Blue Steel missile. But by this time, the high-altitude V-bombers were becoming increasingly vulnerable to air defence missiles. Launched from a ‘stand-off’ position outside the range of enemy air defences, Blue Steel could fly as a small, pilotless plane. However, its unreliability and limited range meant Blue Steel was already out of date when it entered service in 1963.

This aircraft behind me, the Avro Vulcan B2, was armed with the Blue Steel missile while serving at RAF Scampton and RAF Cottesmore at the height of the Cold War. It was kept in a constant state of readiness known as Quick Reaction Alert. This Blue Steel missile was acquired by Imperial War Museums in 1978.

In 1952, the US tested its first thermonuclear bomb – it was 1,000 times more powerful than the atom bomb dropped on Hiroshima, with 10.4 megatons of TNT producing a 4 miles wide mushroom cloud. In comparison, the bomb dropped on Hiroshima was just 15 kilotons.

The Soviet Union successfully tested its first thermonuclear weapon in 1953 and once again, Britain was not that far behind.

On schedule, Britain dropped its own H-bomb over Christmas Island on 8 November 1957 with a yield of over a megaton. 

Over 1957 and 1958, both atomic and thermonuclear weapons were tested over Christmas Island and Malden Island in the Pacific as part of Operation Grapple.

During the tests, British servicemen on the ground reported that the flash of light from the explosions was so bright that, even though they were facing away from the blast and had their hands over their eyes, they could see the bones in their hands. For miles beyond the impact zone, birds, fish and other marine life perished. The long-term effects of radiation contamination on the servicemen and the islands’ inhabitants are still being researched, but they include an array of serious health issues, not just on those present during the tests but passed down through subsequent generations.

Herbert York: In 1957, the British tested their first hydrogen bomb. I happened to be there as one of two American representatives. We were not at all privy to the design of the bomb, there was no exchange of detailed information whatsoever. So I tried to estimate the yield of the bomb, the British didn't even tell us that and I did the best I could, trying to put my hand out and measure with my fingers the size of the fireball. And I was surprised at how small it was. And so I formed the opinion that the British were not on the right track, that they hadn't yet got what we call the Teller-Ulam design. I later learned I was wrong and that they just simply had built it too small. And it was now, I believe, a quite sophisticated approach to the question.

The break in the Manhattan project was not the end of US-UK collaboration on nuclear weapons.

From the end of the Second World War, the US held some of its bomber force in bases across Europe so that its aircraft would be within range of the Soviet Union. In 1953, the United States committed nuclear weapons to its NATO allies, establishing a nuclear presence in Europe.

Then, in 1958, the US-UK Mutual Defence Agreement was signed. Britain and the United States were now able to exchange nuclear materials, technology and information once again. The Special Relationship had been restored. And it wasn’t long before Britain was entirely reliant on America for its nuclear weapons.

To maintain its place as a global nuclear power, pressure was mounting on Britain to create its own ballistic missile to replace the nuclear deterrent carried by the V-bombers. However, Britain’s attempt to create an IRBM, an intermediate-range ballistic missile, in the form of Blue Streak was cancelled in 1960 before it even entered production due to escalating costs.

Britain turned to its American allies and ordered a series of US-made Skybolt ALBMs, air-launched ballistic missiles. Unfortunately, due to continued complications, Skybolt was cancelled in 1962 and Britain’s nuclear deterrent relied on Blue Steel - until Polaris.

Polaris was an American-designed submarine-launched intercontinental ballistic missile which entered service with the Royal Navy in 1968. Launched from underwater, the Polaris maintained a threat to the enemy even if a surprise nuclear attack had destroyed land-based nuclear force. The missiles were developed at Aldermaston and were carried by four British Resolution-class nuclear submarines. Each submarine held 16 missiles. Polaris became Britain’s main nuclear deterrent for the remainder of the Cold War and the V-bombers were withdrawn from their nuclear role.

Behind me is a Polaris A3TK on display at IWM Duxford. It has a Chevaline warhead, a later modification designed to increase the potential of Polaris being able to penetrate Soviet anti-ballistic missile defences. This missile is a drill version, used by the Royal Navy for practice. The acronym AIM printed on the side stands for Active Inert Missile. This means that it contains all of the working parts necessary for training, such as the electrical systems, but cannot be launched.

The need to scale back nuclear tests was recognised early on. From November 1958 to September 1961 – the US, UK, and USSR even observed an informal moratorium on nuclear tests.

But testing and development continued to escalate.

In 1961 the world’s largest ever nuclear weapon was detonated by the Soviets - a 58 megatons H-bomb called Tsar Bomba – The mushroom cloud was 37 miles high. Nuclear testing reached a peak in 1961-1962 when 340 megatons were detonated in the atmosphere by the United States and Soviet Union.

Herbert York: We thought at the time, and I think it's been confirmed by the Russians since, that if that bomb had been built in a standard fashion, if there had been no attempt made to reduce the radioactivity, it would have yielded a hundred megaton, so we always thought of that as the only test essentially of a one hundred megaton bomb.. We now know that Sakharov tried to prevent the explosion of that bomb. And Khruschev apparently said, you're a brilliant scientist and you understand those things, but I understand politics. Kennedy's response is also interesting. Kennedy resisted the idea of an immediate American response, that is an American test. Eventually that became obvious that the Russians just... there was no containing them, and we essentially did the same thing. We went and, you know, we got bombs from wherever we could find and took 'em to Nevada and shot them just in order to respond to these Russian tests. It was a crazy period.

In 1963, after years of negotiations, the Partial Nuclear Test Ban Treaty, which prohibited nuclear weapons tests in the atmosphere, outer space and underwater, was signed by Britain, the United States and the Soviet Union. Other countries followed but some have still never signed it.

The nuclear age was indeed a period of escalation avoidance. World leaders went to great lengths to limit their use throughout the Cold War; summits were organised, and treaties were signed with the aim of preventing all-out nuclear war.

Meanwhile, public dissent was a consistent presence in the UK. The Campaign for Nuclear Disarmament, or CND, was founded in 1957 to advocate for a global ban on nuclear weapons. The organisation led popular protests throughout the 1960s.

PARIS –

After the signing of the Partial Nuclear Test Ban Treaty in 1963, CND membership fell but it had a resurgence in the 1980s, largely owing to the US and British governments stating that American cruise missiles would be based in Britain. By 1985, CND numbers had risen again to over 100,000.

Today, CND actively campaigns against Trident, NATO and nuclear power.

In 1980, the British government announced its plans to replace the ageing stock of Polaris missiles and ordered the American Trident II D5 missile system two years later. Trident went into service with the Royal Navy in 1994 and remains Britain’s main nuclear deterrent.

Four Vanguard-class nuclear-powered submarines carry Trident, each with the capacity to hold up to 8 missiles. At least one nuclear-armed submarine is constantly on patrol.

The British government states that it is “committed to the long-term goal of a world without nuclear weapons” and it remains dedicated to the Treaty on the Non-Proliferation of Nuclear Weapons, which came into force in 1970. Nonetheless, it maintains a constant nuclear deterrent stating that it is required “to preserve peace, prevent coercion and deter aggression” in order to protect Britain and its NATO allies from countries that are “increasing and diversifying their nuclear capabilities”.

In January 2021, the Treaty on the Prohibition of Nuclear Weapons came into force – an international agreement to prohibit nuclear weapons, leading towards their total elimination. To date, Britain and other NATO members have not voted, except for the Netherlands which voted against.

Britain will maintain its continuous at-sea deterrence and it is estimated that the Vanguard-class submarines carrying Trident missiles will be replaced by a Dreadnought-class fleet by the 2030s, hosting existing Trident missile stock.