A recent Royal Navy test of the missile that carries Britain's nuclear deterrent failed within seconds, it has emerged, raising new questions about the deterrent's viability at a time of elevated nuclear tensions.
First revealed by the Sun newspaper, the US-manufactured Trident missile was launched from the submarine HMS Vanguard off the east coast of the US.
However, instead of flying the planned thousands of miles before coming down in the southern Atlantic Ocean, it crashed into the sea near the launch site.
It is the second failed Trident test in a row. The last was in 2016, when another missile fired from a submarine near Florida malfunctioned in flight and veered off course towards the US mainland.
The incident was controversial at the time not just because of its implications for the credibility of the British nuclear deterrent, but also because of its timing.
The malfunction occurred a month before the UK parliament voted resoundingly to renew and replace the deterrent.
But it did not become public knowledge until the start of 2017, with then-prime minister Theresa May reluctant to say when she had become aware of the failure.
Britain has maintained a nuclear deterrent since 1967, with one of four nuclear-armed submarines out on patrol at all times.
Its launch protocol is highly specific: If the crew of the submarine establishes that the UK itself has suffered a devastating attack, they are to open a letter signed by the prime minister instructing them as to whether or not to launch the missiles.
The letter is kept secret until that point, thus enhancing the deterrent with an element of ambiguity.
Powder keg
News of the latest failed test comes just as worries about nuclear weapons are rising to a point not seen in decades.
Last week, reports from the US said that the country's intelligence officials are increasingly concerned that Russia may soon try to launch a nuclear weapon into space, keeping it in low Earth orbit as a perpetual threat.
Their concern is reportedly so urgent that top US diplomats have consulted with counterparts in India and China to find a way to talk Russia out of the potential move.
Russia has already made vague nuclear threats over the Ukraine war. While few anticipate that Vladimir Putin would launch a full-scale attack on a NATO country, some worry he could deploy a tactical weapon on the battlefield.
Given the prospect that a re-elected Donald Trump could withdraw from NATO altogether – he recently said that any country that does not pay its fair share would be left at Russia's mercy – a German government minister recently penned a striking opinion piece calling for the British and French deterrents to be reoriented toward defending the entire European continent.
Meanwhile, with arms control treaties between the US and Russia in tatters, China has continued to expand its nuclear arsenal, while North Korea continues to conduct sporadic tests of nuclear-capable intercontinental ballistic missiles.
Iran also remains a worry, with the head of the UN's nuclear watchdog warning that the government in Tehran is not being "entirely transparent" about its enrichment programme.
