Becoming the British prime minister means giving top-secret orders—immediately—that could determine the fate of the world.
Following a landslide victory for the Labour Party, Britain has a new leader. The moment Keir Starmer is officially made prime minister of the United Kingdom, he will be given a flurry of briefings, piles of documents, and the urgent business to run the country. Lurking among those papers is a moral land mine.
Starmer will be given a pen and four pieces of paper. On each paper, he must handwrite identical top-secret orders that—hopefully—no other human being will ever see. The previous set of orders, written by outgoing Prime Minister Rishi Sunak, will then be destroyed, unopened. These top-secret papers are called the “letters of last resort.”
Since 1969, Britain’s nuclear deterrent has operated at sea, with nuclear missiles that could be launched from at least one continuously deployed submarine. Destroying those vessels would eliminate the United Kingdom’s nuclear deterrent, so the secrecy of the patrolling submarine’s location is paramount. Once deployed, the submarine may not transmit messages, only receive them, to maintain its crucial cloak of concealment.
Today, there are four submarines—one always on patrol—which is why there are four identical copies of the letters. Each handwritten letter is placed inside a safe, which is housed inside another safe, on board the nuclear-armed submarine. Right now, one of those submarines is patrolling the world’s oceans, its location known only to a tiny number of people at the highest levels of the British government.
During the Cold War, British authorities constantly feared that London could be wiped out in a surprise nuclear attack by the Soviet Union. If the British government ceased to exist in a blinding flash of atomic light, and everyone in the civilian chain of command was dead, who would have the authority to launch a counterattack? Without the credible threat of a “second strike” in response to a nuclear assault on the capital, Britain lacked a deterrent.
The letters of last resort are the solution to that dilemma: They allow the prime minister to issue orders for a counterattack from beyond the grave. If the submarine captain has reason to believe that London has been destroyed in a nuclear blast (one of the cues is said to be that the BBC has stopped broadcasting), then the captain is to make every attempt to verify that the British government no longer exists. Once satisfied that the worst has indeed taken place, only then may the captain open the two safes, unseal the letters, read their contents, and execute the order from the now-deceased prime minister.
