UK Labour Party leader Sir Keir Starmer last week declared for the third time that he would, in office, authorise the firing of nuclear missiles.

A conversation between Starmer and ITV News Political Correspondent Harry Horton—as Starmer was visiting the BAE Systems shipyard where Britain’s nuclear-armed submarines are built—was chilling. Horton asked, “If Britain was under attack would you be prepared to push the nuclear button… even it means potentially killing millions of people?”

Starmer replied, “The deterrent only works if there is a preparedness to use it—so that is a clear answer to your question.”

With the Conservative government mired in crisis and hated by millions, Labour is expected to win the general election later this year. Starmer’s statement is an essential element of Labour’s pitch to the ruling class that it can be trusted with office, under conditions in which Britain is embroiled in major military conflicts all over the globe.

Significantly, Starmer’s first public confirmation that he would authorise nuclear strikes took place on February 10, 2022. Asked by the BBC whether he would be willing to use nuclear weapons, he replied, “Of course.” This was just 14 days before Russia’s invasion of Ukraine. In January this year, while in Estonia, Starmer answered yes to the same question.

Starmer has since then boasted that Labour is the “party of NATO”, as he has enthusiastically backed every global crime of British imperialism, from the bloody slaughter in Ukraine, to supporting Israel’s genocide in Gaza and advanced plans for war against Iran and China.

The Labour leader is one of three senior political figures—including two prime ministers—who have publicly declared over the last decade that they would take actions meaning the end of civilisation.

That they were asked if they would do so was the response of Britain’s ruling class to the election of Starmer’s predecessor as Labour leader, Jeremy Corbyn, when he hesitated to pledge to launching a nuclear strike.

After winning a general election, a prime minister is privately briefed by a leading military figure and then told to write instructions in a letter to each of the four nuclear-armed submarine commanders, based on the scenario that Britain has been hit by a nuclear bomb and the prime minister is dead. The “letters of last resort” instruct the commanders on whether and when to use nuclear weapons. Since Britain obtained nuclear weapons, following the decision of the Atlee Labour government in 1947, every prime minister has signed these letters.

The destructive power of Britain’s arsenal is staggering. Each of the four Trident submarines carries 40 nuclear warheads, each with an explosive yield of 100 kilotons—at least six to eight times more destructive than the 15-kiloton bomb dropped on Hiroshima by the US at the end of World War II. Each warhead can obliterate up to one million people.

Corbyn is a lifelong member of the Campaign for Nuclear Disarmament and was chairman of the Stop the War Coalition when he took the leadership of Labour on a massive mandate against war and austerity in September 2015.

Within three weeks of taking office Corbyn was asked, at Labour’s annual conference in Brighton, if he would use nuclear weapons if elected prime minister. He replied “no” and stated his opposition to renewing the Trident nuclear programme.

This set into motion a ferocious campaign by the Blairites—backed by the Conservative government, intelligence agencies and the military—which resulted, in the space of five years, in Corbyn’s removal as Labour leader and expulsion from the parliamentary party.

Even before his Brighton statement, a senior serving British general told the Sunday Times, on September 20, 2017, that if Corbyn came to power there “would effectively be a mutiny… You would see a major break in convention with senior generals directly and publicly challenging Corbyn over vital important policy decisions such as Trident, pulling out of Nato and any plans to emasculate and shrink the size of the armed forces. The Army just wouldn’t stand for it.”

On July 18, 2016, after taking the Conservative Party leadership five days earlier and signing her own “letters of last resort”, Prime Minister Theresa May was asked in Parliament by the Scottish National Party’s George Kerevan, “Is she [May] personally prepared to authorise a nuclear strike that could kill 100,000 innocent men, women and children?”

May replied, “Yes,” and denounced “the suggestion that we could have a nuclear deterrent but not actually be willing to use it, which seemed to come from the Labour Front Bench.”

During the campaign for the June 2017 general election, the first question asked by BBC journalist Andrew Marr during an interrogation of Corbyn was what would he write in the letters of last resort. “You have to say fire or don’t fire.” Corbyn took a major step in his ongoing capitulation before his Blairite opponents by fudging the issue, saying his “strict instruction” would be to “follow orders when given.”

By this time Corbyn had already abandoned everything he professed to personally believe regarding membership of NATO and the renewal of Trident.  His 2017 election manifesto reaffirmed Labour’s “commitment to NATO” and promised that Corbyn would be “spending at least 2% of GDP on defence…”

A draft of the manifesto dated May 11 had stated, “Any prime minister should be extremely cautious about ordering the use of weapons of mass destruction which would result in the indiscriminate killing of millions of innocent civilians.” This was deleted from the final manifesto published five days later.

The 2017 election was narrowly won by May. Corbyn remained Labour leader until being routed by the Tories’ next leader Boris Johnson in the 2019 general election. As part of the war drive of the imperialist powers against Russia, Corbyn’s 2019 Labour manifesto had implied that the Johnson government was in the pocket of Russian President Putin and attacked him for refusing to “publish the report into possible foreign interference by Russia in UK democracy.”

Johnson fell from office three years later thanks to the murderous policies he pursued during the initial stages of the COVID-19 pandemic and was briefly replaced by Liz Truss as prime minister. When Truss was asked during a Tory leadership husting in August 2022 if she would launch nuclear missiles that “would mean global annihilation,” she replied, “I’m ready to do that.”

That all those auditioning for office before the ruling elite must now affirm their readiness to kill millions and destroy the planet is a stark warning. No matter who is prime minister and which party they lead, the working class in Britain, like workers internationally, confronts a single party of war. There is no lesser-evil because there is nothing fundamentally to choose between them.

In the UK, the Socialist Equality Party will stand candidates in the upcoming general election rejecting any vote for Labour and its candidates and insisting on the building of a new anti-imperialist and revolutionary leadership to mobilise a mass socialist movement of the working class against war.

In Germany our comrades are fielding a slate of candidates in this summer’s European elections fighting for the same political turn, and the SEP in the United States is fielding Joseph Kishore as its presidential candidate against the would-be Führer Donald Trump and “Genocide Joe” Biden. All these campaigns address the essential task of building the Fourth International, led by the International Committee, to lead the world working class in the overthrow of capitalism.