The Manhattan Project wasn't just an American thing - Here's how capable the UK's nuclear arsenal is

• Nuclear weapons were born during the Second World War.
• The U.S. was the first to build and use them but was helped by the British to make them.
• Yet, despite the U.S. refusing to share information, 70 years ago, the United Kingdom successfully tested its version.

70 years ago, the United Kingdom (U.K) joined the exclusive ranks of nuclear-capable nations. It was a historic day for the country, and it had been a long time coming.

Despite what you may have been told about the Manhattan Project, a lot of the heavy lifting in developing the bomb was done by British scientists. Stitched up at the last minute, the U.K. was forced to go it alone after the Second World War.

But that is all water under the bridge now, as the U.K. stands among the very few nations with a working nuclear deterrent.

Let's look at just how capable the U.K.'s nuclear arsenal is.

Does Britain have a nuclear deterrent?

It most certainly does. The United Kingdom is one of nine nations armed with nuclear weapons (at least officially). Unlike the United States and Russia, the United Kingdom's nuclear deterrent is somewhat more modest.

However, it is still mighty. But, you might be wondering, what is it?

Well, according to the United Kingdom's official page on the matter, since April 1969, the Royal Navy has maintained continuous sea deterrence, with at least one nuclear-armed ballistic missile submarine patrolling the seas undetected at all times, ready to respond to the most extreme threats to the U.K.

Officially, the vessels' main goal is to keep the peace, stop coercion, and discourage aggression against the United Kingdom and its allies.

Called the continuous at-sea deterrent (CASD for short), it has been deemed the most capable, reliable, and cost-effective way to deploy the U.K.'s independent nuclear deterrent.

This currently consists of a fleet of four aging Vanguard nuclear-powered and nuclear-armed submarines. As part of the Trident nuclear program, the class was introduced in 1994. The current vessels are HMS Vanguard, HMS Victorious, HMS Vigilant, and HMS Vengeance.

They were built by Vickers Shipbuilding and Engineering, which BAE Systems now own, between 1986 and 1999 at Barrow-in-Furness. All four boats are based at HM Naval Base Clyde, roughly 25 miles (40 km) west of Glasgow, Scotland. Since the Royal Air Force WE.177 free-fall thermonuclear weapons were taken out of service in March 1998, only the four Vanguard submarines currently carry nuclear weapons for the United Kingdom.

Each submarine can carry up to 16 UGM-133 Trident II intercontinental ballistic missiles. This might not sound like a lot, but remember that each Trident missile contains multiple independently targetable re-entry vehicles (MIRVs) ranging from just a few to several hundred kilotonnes in yield.

A single Trident II missile could deliver eight independently targetable nuclear warheads up to ranges of 4,000 nautical miles (7,400 km) from a Vanguard submarine. That is a pretty scary thought.

The U.K. only keeps the smallest amount of destructive power necessary to ensure that its deterrent is compelling and credible against all types of state-level nuclear threats. The U.K.'s submarines on patrol are at several days' notice to fire and, since 1994, are not pre-targeted at particular locations worldwide.

Like other nuclear nations, the United Kingdom does not officially disclose how it would use its nuclear weapons should the need arise. This, says the United Kingdom government, keeps the deterrent from becoming less effective and makes it harder for a potential aggressor to figure out what to do.

While the current weapons are largely American design and construction, their operation and deployment are entirely independent of the United States. The weapons can only be launched with the express permission of the Prime Minister. This is true even if they are used as part of a NATO response.

How did the U.K. get nuclear weapons?

As we mentioned earlier, The United Kingdom developed and tested nuclear weapons for the first time in 1952. In doing so, it officially became the third to do so in the world, after the United States and the Soviet Union.

But that belies the true nature of the United Kingdom's involvement in developing nuclear weapons. They were instrumental from the start.

During World War II, the U.K. was one of the earliest nations to begin work on nuclear weapons with its so-called "Tube Alloys" project. This started before the more famous "Manhattan Project" and was so top secret that only a few members of the British government knew about its existence.

The project was commenced in the early stages of the war, and a memorandum, entitled "On the Construction of a 'Super-Bomb," outlining how a modest mass of pure uranium-235 could be used to create a chain reaction in a bomb with the force of thousands of tonnes of TNT was co-written by Rudolf Peierls and Otto Robert Frisch at the University of Birmingham.

Soon after, the MAUD Committee was created and advocated for a full-scale nuclear weapons development project. The project's manager, Wallace Akers, purposely adopted the deceptive code name "Tube Alloys."

The MAUD Committee conducted its business in total secrecy. In 1941, it reported that it was possible to construct a bomb and suggested working with the United States to accomplish it.

The British Scientific and Advisory Committee evaluated the report and determined that the bomb should be prioritized. They suggested a trial plant be established in the U.K. to separate U-235, followed by a large-scale plant in Canada.

"Although I am quite content with the existing explosives, I feel we must not stand in the path of improvement, and I, therefore, think that action should be taken," Churchill stated."

As a result, he established the Directorate of Tube Alloys within the Department of Scientific and Industrial Research (DSID), the entity in charge of all atomic resources. For the duration of the conflict, the British atomic project's code name would be "Tube Alloys."

President Roosevelt wrote to Churchill in August 1941 and suggested the two countries collaborate on the development of nuclear weapons. Churchill preferred to keep the more advanced Tube Alloys project separate, and was also concerned with security leaks from the U.S. Ironically, the British project had already been infiltrated by Soviet spies.

However, by 1942 the American teams had become more advanced in their organization and scientific resources. Michael Perrin, the secretary-general of Tube Alloys, noted on a visit to the U.S. that the country would "completely outstrip us in ideas, research and application of nuclear energy and that then, quite rightly, they will see no reason for our butting in."

Despite its successes, due to the spiraling costs of the war effort, the entire British team was eventually absorbed into the Manhattan Project through the Quebec Agreement with the United States. Under this agreement, the two nations agreed to share nuclear weapons technology and refrain from using it against each other or other countries without consent.

A number of prominent British scientists were transferred to the United States to work on the Manhattan Project. However, many British scientists were only given limited roles to restrict their access to sensitive or detailed information.

When the Manhattan Project project proved to be a great success, the British government was under the impression that nuclear weapons were a joint discovery. However, the American Atomic Energy Act of 1946 (aka the McMahon Act) stopped other countries, including the U.K., from getting information about nuclear weapons.

Although there was some further talk of collaboration, the realization, in 1950 and 1951, that British scientists and diplomats with access to information about the Manhatten Project, including Klaus Fuchs, Donald Maclean, and Guy Burgess, were Soviet spies ended any talk of co-operation The U.S. even turned down Britain's request to test an atomic bomb at Frenchman Flat in Nevada.

Since Britain feared losing its status as a great power, it returned to its nuclear project under a new, less anonymous name of "High Explosive Research." The British finally managed to catch up several years after the conclusion of the Second World War and the deployment of two of America's early atomic weapons.

Its first atomic test, "Operation Hurricane," occurred on October 3, 1952, and set off an atomic bomb on the Monte Bello Islands in Australia. Over the next ten years, the British conducted eleven more nuclear weapons tests in Australia.

Seven of these tests were conducted at Maralinga between 1956 and 1957.

Building on these tests, the British began developing and building larger, more powerful hydrogen bombs that concluded with "Operation Grapple." This consisted of nuclear tests in the Pacific, and the British hydrogen bomb program showed that Britain could make thermonuclear weapons.

This eventually led to the McMahon Act being changed. The U.S.–U.K. Mutual Defense Agreement was signed in 1958, and the U.S. and the U.K. have worked extensively on nuclear security issues ever since.

As part of the nuclear 'Special Relationship' between the two countries, secret scientific information and fissile materials like uranium-235 and plutonium have been passed back and forth.

Since Blue Streak (an early British Intermediate-range ballistic missile) was canceled in 1960, the U.K. hasn't planned to build its own delivery system.

Instead, it has purchased U.S. delivery systems and armed them with warheads made by the U.K.'s Atomic Weapons Establishment (AWE) and its predecessor. Under the Polaris Sales Agreement of 1963, the U.S. gave the U.K. Polaris missiles and technology for nuclear submarines.

Under another project, "Project E," the U.S. sent nuclear bombs, missiles, depth charges, and artillery shells to the Royal Air Force and the British Army of the Rhine until 1992. Since 1949, nuclear-capable American aircraft were also based in the U.K., but the last of them was withdrawn in 2008.

In 1982, the Polaris Sales Agreement was changed, which let the U.K. lease Trident II missiles. Since the U.K. stopped using its tactical WE.177 bombs in 1998, the Trident has been the only nuclear weapons system used by the U.K.

Today the United Kingdom is also one of the five nuclear-weapon states that signed the Treaty on the Non-Proliferation of Nuclear Weapons.

How does the United Kingdom's nuclear deterrent work under NATO?

As long as there are nuclear weapons, NATO will always be a nuclear alliance.

Since 1962, the U.K. has said it will use nuclear power to defend NATO. Nuclear deterrence is critical to NATO's overall strategy, and the U.K.'s deterrent helps safeguard European and Euro-Atlantic security. NATO membership sits at the heart of U.K. policy, and they are committed to a credible and united nuclear Alliance.

Although the U.K.'s nuclear deterrent is assigned to the defense of NATO, the U.K. retains complete operational control over its use. According to the U.K. government, if nuclear weapons are part of a larger NATO response, only the U.K. Prime Minister can permit using them.

Nuclear is still a big part of the U.K.'s long history of working with the U.S. on defense, making the trans-Atlantic area safer. The U.K. and the U.S. work together on nuclear issues like deterrence policy, the safety, security, and advanced manufacturing technologies of warheads. This helps both countries lower the costs of building and running nuclear weapons as a deterrent.

France, another nuclear power, and the U.K. also have a strong and vital relationship and work daily on nuclear issues to help keep Europe safe. This includes working together through the Teutates Treaty of 2010, which lets both nations share research facilities and collaborate on technology.

The U.K. also says its government works with international partners to reduce the threat of nuclear terrorism and conduct research to support arms control and verification.

What is the future of the U.K.'s nuclear deterrent?

The U.K. considers its independent nuclear deterrent essential now and in the future. It will remain a crucial part of its national security strategy for as long as the world's security situation requires it. In 2016, Parliament decided to renew its nuclear deterrent and keep CASD.

The U.K. government says this will be achieved by replacing the existing Vanguard Class submarines with four new Dreadnought Class submarines. The Vanguard submarines have been in use since 1992 and are aging.

The new Dreadnought submarines are scheduled to be introduced in the 2030s and should have a lifespan of around 30 years apiece. Although the information is relatively thin on the ground, it has been announced that the first three new submarines will be called Valiant, Warspite, and King George VI.

These choices of names for the class and its planned ships are interesting in and of themselves, as they will be the latest iterations of some of the Royal Navy's most famous warships from the past. Dreadnought, for example, was the great granddaddy of the mighty battleships that would rise during the early to the mid-20th century.

She effectively ushered in a new era of warship design. An omen, perhaps?

These new submarines will be some of the most advanced war machines ever made. They will be designed and built in the U.K. and use world-leading and cutting-edge technology to make them very powerful and dangerous.

The program is still on track and on budget, and the first new submarine will still go into service at the start of the 2030s.

The U.K. will replace its nuclear warheads as part of the renewal program, alongside the submarines that carry them.

They are currently working with the Atomic Weapons Establishment to build the highly skilled teams, facilities, and skills needed to complete the so-called Replacement Warhead Program.

To this end, the U.K. will keep working closely with the U.S. to ensure that their warheads are still compatible with the Trident Strategic Weapon System, which is used by both the current Vanguard Class submarine fleet and the future Dreadnought Class fleet.

This investment in the future security of the U.K., so the U.K. government declares, will ensure that the U.K. has a minimum, credible, independent nuclear deterrent for as long as the global security situation requires it.

How much does Trident cost the U.K.?

The cost of the United Kingdom's current nuclear deterrent depends on your meaning. For example, you need to consider the cost of building it and the running cost of maintaining it. Other factors are involved, like the employment it creates and other intangibles, like the safety it offers.

However, the annual budget for the Ministry of Defence is roughly £40 billion. Of that, Trident's yearly running expenses are expected to be about five percent to six percent of this, or roughly £2.5 to 2.8 billion. While that sounds like a lot, it must be put into perspective.

Trident amounts to about 1% of the government's spending on social security and tax credits or the weekly amount spent on the NHS.

As for the current system's initial costs, this has since been assessed at £12.52 billion by the Strategic Defense Review in 1998. This amounts to about £22.56 billion today.

The system's operating costs were from three percent to 4.5 percent of the annual defense budget when implemented in 1994. In 2005–2006, it rose to a range of five percent – six percent and had stayed there ever since.

All is well and good, but the current Trident system is in dire need of replacement. The estimated cost of replacing the present class of nuclear submarines is £31 billion. To cover additional expenses or spending exceeding the estimate, an additional £10 billion has also been set aside as a contingency fund.

Approximately £4.8 billion of the government's budget has been earmarked or spent on developing the Trident replacement. And that is primarily only for the new Dreadnaught-class submarines.

It will cost about £250 million to keep the current Trident missiles operational into the first half of 2060.

The cost of operating the present Trident submarine fleet until 2028, which is four years longer than anticipated, is estimated to be between £1.2 and £1.4 billion. According to the House of Commons Library, savings from the Submarine Enterprise Performance Programme are anticipated to offset this somewhat.

The system's running costs will cover any additional expenses resulting from a postponement of the launch of Trident.

But what about the other benefits beyond having a nuclear deterrent does the U.K. get?

Well, designing, constructing, operating, and maintaining the independent nuclear deterrent of the U.K. is a national effort that directly supports tens of thousands of employees throughout the nation.

Thousands of people work at the HM Naval Base Clyde, making it one of Scotland's most significant employment hubs. Many of these workers settle in the West of Scotland once their military careers are over.

As part of plans to transform the site into the U.K.'s Submarine Centre of Specialization in a £1.6 billion investment program, a facility for training top-tier submariners opened in 2020.

Submarines are built at the BAE Systems Shipyard in Barrow in Furness, where the Submarine Academy also offers training and apprenticeships. Rolls-Royce at Derby produces the nuclear propulsion systems, and Babcock supports and maintains operational submarines at naval sites in Faslane and Plymouth.

AWE is one of the major employers of scientists and engineers in the U.K., too, employing thousands of workers in the production, upkeep, and assurance of the U.K.'s nuclear warheads and 1,700 scientists and engineers.

Through the supply chain, some 2,500 enterprises maintain the U.K.'s independent nuclear deterrent, supporting thousands more jobs throughout the U.K.

There are also intangible benefits too. While the nuclear deterrent is expensive to operate, maintain, and refurbish, the reassurance to national security it provides is, arguably, priceless.

The U.K. government says Trident "is an investment in the protection of generations to come, and the ongoing costs form only a small part of the government's overall defense budget."

Does the U.K. have any defense against nuclear weapons?

It most certainly does.

But to be able to shoot down incoming missiles, one must know where they are coming from. This is where the first part of the system is sophisticated surveillance systems.

This is where RAF Flyingdales comes into play.

This radar base is integral to the U.K.'s Ballistic Missile Early Warning System (BMEWS). Data gathered at RAF Fylingdales is shared between the United States and the United Kingdom as part of intelligence-sharing agreements, for example, the United Kingdom – United States of America Agreement (UKUSA).

Its main objective is to alert the British and American governments of a potential ballistic missile assault as part of the so-called four-minute warning during the Cold War. This radar station remains a British asset operated and commanded by the Royal Air Force.

Interestingly, it also forms one of three stations in the United States BMEWS network. Thule Air Base in Greenland and Clear Air Force Station in Alaska are the other two sites in the network.

Fylingdales collects data that is ultimately and unrestrictedly shared with the U.S., where it feeds into the U.S.-Canadian North American Aerospace Defence Command at Peterson Air Force Base in Colorado Springs.

Great, but how would the U.K. intercept and destroy incoming missiles?

One of the main layers of defense is, fittingly, the Royal Navy. Within its naval assets are a special kind of warship, the Type 45 Destroyer. Also called the D or Daring-class, these are state-of-the-art guided missile destroyers.

Designed from the ground (well sea level) up as anti-aircraft and anti-missile ships., the Royal Navy can currently field six of them. To this end, they operate around the PAAMS (Sea Viper) air-defense system utilizing the SAMPSON Active electronically scanned array (AESA) and the S1850M long-range radars.

The Aster missiles were created to intercept and eliminate air threats, including cruise, anti-radiation, and even sea-skimming supersonic anti-ship missiles. These threats include high-performance combat aircraft, UAVs, and helicopters.

The Aster 30 Block 1 and Block 1 NT was also built to defend against ballistic missiles.

The existing fleet is also scheduled for a significant upgrade soon to integrate the ASTER 30 Block 1/NT missile. According to an official U.K. Government press release on the subject, the improved defense system will assist U.K. forces in fending off the growing dangers posed by anti-ship ballistic missiles at sea by developing the missile into a maritime form.

The ASTER 30 Block 1 missile was previously exclusively employed in French and Italian land systems.

The U.K.'s Ministry of Defence has given Maritime Ballistic Missile Defence an initial contract for this work that, when completed, will be worth more than £300 million and support more than 100 jobs across the U.K., including highly skilled technological positions in places like Stevenage, Cowes, Bristol, and Bolton.

But this may only be a stop-gap as plans are afoot to replace them with even more capable Type 83 Destroyers sometime in the 2030s.

All is well and good, but does the U.K. have anything land-based that can knock out incoming nuclear missiles?

As it happens, it doesn't at present, at least not yet,

it was recently announced that the U.K. had been granted permission by the United States Government to buy a new ballistic missile defense radar and related command, battle management, and communications hardware. As reported by the U.K. Defense Journal, an official press release stated that "the Government of the United Kingdom has requested to buy one (1) Ballistic Missile Defense Radar (BMDR); and two (2) Command and Control Battle Management and Communications (C2BMC) user nodes (with network capability required to connect to the C2BMC System to support radar operations)."

The deal also includes other elements vital to the system's long-term maintenance and continued operation.

"Also included are the design and construction of a combined radar-equipment shelter;  encryption devices, secure communication equipment, and other required COMSEC equipment to support radar operations; spare and repair parts, support and testing equipment, publications and technical documentation, personnel training, and training equipment, U.S. Government and contractor engineering, technical and logistics support services, and other related elements of logistical and program support. The total estimated program cost is $700 million."

All very promising, but the system won't become a reality for several years yet, most likely into the 2030s. This is due, as always, to the cost. At present, the agreed deal has been postponed for now.

Apart from that, little else is known about the planned system. However, according to some sources, the system will be installed in Cyprus. The Royal Air Force still controls and operates the radar station at RAF Fylingdales, but it is also one of three stations that make up the BMEWS network of the United States.

And that's your lot for today.

The United Kingdom was one of the first nations to develop a nuclear weapon. Despite some early setbacks after the Second World War, they now sit behind one of the most powerful nuclear arsenals on the planet.

For an island nation with a history of reliance on her navy, it should be no surprise that the U.K.'s nuclear deterrent is equally heavily invested in her maritime capabilities. While maintaining the nation's nuclear deterrent can sometimes be a political hotcake, the U.K. is committed to maintaining and upgrading it for the foreseeable future.