16 September 2025

Is the United States moving nuclear weapons to the United Kingdom?

Preface

I wrote this in late September 2023, and updated it on 27 January 2024. The questioner likely was motivated by the Russia - Ukraine war. Um Russian Special Military Operation. Invasion of Ukraine by Russia? You get the idea.

Has the U.S. recently moved nuclear bombs to the UK?

No, the United States hasn’t moved nuclear weapons to the UK. Well, not yet and even if we eventually do, not for awhile. More on that in a moment. First, a bit about why it might not even be necessary.

The UK already has nuclear weapons

England developed nuclear bombs in 1953, and has been able to deliver them on submarines since 1969. That is to say, the UK already has nuclear weapons on its nuclear-powered submarines. According to the sometimes lefty or maybe just contrarian Bulletin of the Atomic Scientists (the cheery people with the Doomsday Clock), 120 of the UK’s stockpile of 225 nuclear warheads are operationally available.

UK as nuclear monad?

No, I'm not referring to monads in Haskell, nor in APL!

The UK is the only “nuclear weapons state” which has a single nuclear platform: Four Vanguard-class nuclear-powered ballistic missile submarines (SSBNs). To be precise, the SSBNs are the nuclear platform and the submarine-launched ballistic missiles (SLBMs) are the nuclear delivery system.

The UK limits its SSBNs to carrying no more than 40 nuclear warheads at a time. Prior to 2010, each submarine carried 48 nuclear warheads. The reduction from 48 to 40 was probably a strategic decision rather than a tactical one, i.e. there is still room for the extra warheads.

The nuclear warheads are named Holbrook. All 120 have the same name. More on that in a moment too.

Only one of the four submarines is at sea at any time. Two stay in port, while a fourth undergoes routine maintenance and repairs. This is why it makes sense to have 120 operational warheads (SLBMs): 40 go with the one submarine at sea. 40 remain on each of the two submarines anchored at dock but ready to be deployed if needed. Since the fourth submarine is undergoing maintenance, it wouldn’t do to have nuclear warheads on board! So, 40 x 3 = 120

Nuclear triad

In contrast to the UK, the US has a nuclear triad. That means that the US can dispatch nuclear warheads in three different ways: by Polaris submarine, by airplane, and by land.

“Land” doesn’t mean putting a nuclear bomb on a flatbed truck and just driving it up to wherever needs to be bombed, shoving it over the side, then driving away and detonating remotely from a safe distance. Instead, nuclear-tipped ICBMs (intercontinental ballistic missiles) get the nukes where they are needed. ICBMs are launched from one continent, travel quite low, though always above ground, to hit a target on another continent. ICBMs can be conventional too, i.e.have non-nuclear bombs. There are a few genuine and many CGI videos of ICBMs in action (most are courtesy of defense contractors). All depictions are impressive.

ICBMs are distinctly different from nuclear bomb delivery by airplane. In the latter case, the planes are flown to the destination, then the nuclear missiles are dropped from a height and detonate slightly above their targets.

US nukes in the UK

There is is an active movement opposed to situating any US nuclear missiles in the UK. I do wonder if the UK Campaign for Nuclear Disarmament (CNDUK), pictured below near RAF Lakenheath, is aware that there are already UK nuclear weapons in the UK.

Perhaps they only want British nukes?

Would that be frowned upon by Prime Minister Keir Starmer as unacceptably nationalist sentiment? I'm not sure, and I'm not being facetious.

For example, consider a recent statement by French President Emmanuel Macron. In his speech of 5 March 2025, Macron said:

Our nuclear deterrence protects us. It is thorough, sovereign and French from start to finish, since 1964...
people standing in green grass in UK holding signs
CNDUK No US Nukes Day of Action demonstrators

In a very real sense, the US has had nuclear weapons in the UK for awhile. According to The Bulletin, emphasis mine,

The United Kingdom’s nuclear deterrent relies heavily on American nuclear infrastructure, to the point where its own independence has long been in question. The UK does not own its own missiles, but has title to SLBMs from a pool of missiles shared with the US Navy.

Also, the UK's SLBMs (Holbrooks) are supposed to be very similar to the US W76-0 warhead.

09 August 2025

What happens if a supercomputer is used to mine bitcoins?

This has happened. I wrote about incidents of supercomputers being used to mine cryptocurrency a few years ago: Subverting computing research for fool's gold.

Bitcoin

NSF sponsored-researcher misused supercomputers to mine bitcoin via BBC June 2014:

A researcher has been suspended from a US national agency for misusing supercomputers to mine bitcoins at two universities. In a report, the National Science Foundation (NSF) revealed that more than $8,000 worth of bitcoins had been generated from NSF-funded computers... It is claimed that the unnamed researcher used remote access software and may have been attempting to cover his tracks.

So, he knew it wrong, tried to hide what he did including remotely accessing the supercomputer from Europe, and got caught.


The researcher’s access to all NSF-funded supercomputer resources was terminated, and after the NSF Office of Inspector General investigated (pp. 30-31), he was suspended from any further activities government-wide.

Dogecoin: Klondike operations

In February 2014, yet another researcher, at Harvard University, was caught mining a different cryptocurrency, Dogecoin. He used Harvard's Odyssey, a high-powered network cluster, which uses thousands of CPU cores, to mine Dogecoin. Harvard Crimson described the incident rather colorfully:

“Any participation in “Klondike" style digital mining operations or contests for profit requiring Harvard-owned assets to examine digital currency key strength and length are strictly prohibited for fairly obvious reasons,” 

Unusually high electric power consumption was what alerted Harvard to the situation. Since significant resources were wasted as part of the illicit mining activities, blowing through a lot of funds budgeted for research, the assistant dean for research computing wrote this notice: Harvard Dogecoin Mining on Pastebin. It has since been deleted. This was the URL https://pastebin.com/P8kvWqSG

All's well that ends well. Maybe? A few days after the "Klondike mining operation", several current students received the following email invitation from a mysterious HBS alumnus named John Harvard Bitcoin

“Are you the secret DOGE miner? I just started the Harvard Bitcoin Club and would like to invite you to join. The goal is to start an ‘open club’ that promotes Bitcoin education.”

This led to the establishment of periodic gatherings of the Bitcoin Club. Founder John Harvard Bitcoin paid for meeting materials and reimbursed the cost of attendee meals in Bitcoin. 

Supercomputers versus GPUs

Graphics processing units (GPU) are often integrated on a regular processor (chip). Sometimes, especially for gaming or applications like Second Life, a computer will have a "traditional" processor chip AND a stand-alone "dedicated" GPU, activated only as needed for graphically-intensive applications. GPUs are very fast for certain purposes.