The British left will not follow Trump into war

Should Keir Starmer back these strikes, he risks splitting his entire political movement.

On Thursday, Donald Trump said he would make a decision on direct US involvement in the Iran-Israel conflict within two weeks. In the end, it was a little over two days. On Saturday night (21 June), the US bombed Iran’s nuclear sites, directly inserting America into the conflict in the Middle East.

These events have ramped up the pressure on Keir Starmer. The UK and the US are close allies; Starmer’s rapport with Trump is something he is likely keen to protect (in the photo call for the signing of the US-UK trade deal, Trump said: “The UK is very well protected. You know why? Because I like them”). In a statement on Sunday morning, the Prime Minister tacitly backed the attacks, saying “the US has taken action to alleviate [the] threat” of the Iranian nuclear programme, and called for Iran to return to the negotiating table. Though Starmer’s position remains aligned with the UK’s European allies (France’s president, Emmanuel Macron has similarly called on Iran to negotiate), he will likely face pressure from the US (and from Trump himself) to increase British involvement in this war. But will he do it?

This is an extremely delicate situation. The UK would be on difficult legal ground if it did get directly involved militarily, as it has not been directly attacked, nor have any of its Nato allies. Equally, it was not in in the country’s interests to see an Iranian escalation which threatened shipping lanes in the Strait of Hormuz, or the UK’s military bases in Cyprus. Speaking on Sunday morning, the Business Secretary Jonathan Reynolds said that while the UK was not involved in direct action overnight, the UK military would be prepared to defend “key allies” in this conflict. And should Starmer back Trump further, it is likely to cause deep political tension. Inside the Labour Party and on the left, it already is.

Though the UK is not directly involved in the Israel-Iran conflict (and was not involved in last night’s strikes), the same criticisms which have plagued the government on the ongoing war in Gaza have been applied here. Britain continues to supply arms to Israel through the F45 fighter jet programme and its belated sanctioning of far-right members of the Israeli government (Itamar Ben-Gvir and Bezalel Smotrich received sanctions last week) has been widely criticised.

The risk of active British involvement in the war in the Middle East will not likely sit well with some Labour MPs. The scars of the Iraq War run deep among Labour politicians and party members. One back-bench MP was clear: there are a lot of people in the Labour Party who don’t want to go to war in Iran. While this is mostly concentrated among the old guard of MPs (those elected pre-2024), the MP continued, members of the new intake share the same apprehension. They added that this concern could even stretch to the cabinet, and that it would be better for Starmer to align the UK with its European partners and Canada, rather than remain at the beck and call of Trump and the US. The MP said Starmer should stick with Europe. “Britain has to have a recalibration of who they’re dealing with,” they said.

How Starmer deals with this conflict is also being watched closely by the left-wing coalition which is forming outside the party. Among this broad extra-parliamentary group there is agreement that the UK must not be led into this conflict to serve US interests. On 21 June, the Palestine Solidarity Campaign marched from Russell Square to Westminster, with speakers including the independent (former Labour) MP Zarah Sultana, Paloma Faith, Jeremy Corbyn and the Green party leadership candidate Zack Polanski. This group is, of course, dead against any direct UK involvement in the conflict.

Prior to the US strikes on Iran, Corbyn told me: “The last Labour government made the mistake of following the US into a catastrophic war and refusing to build its own, independent, ethical foreign policy. Human beings abroad paid the price.” The former Labour leader, who recently brought a ten-minute rule bill calling for an independent inquiry into the UK’s involvement in Gaza, called on the government “to learn the lessons of the past, otherwise it will be remembered for the less secure and less peaceful world it has helped to create”. Though Corbyn has not spoken publicly about last night’s events, he will certainly be deeply opposed to further UK involvement.

His sentiments were similarly echoed by Polanski, who told me on Friday: “Starmer claims to support de-escalation – yet continues to back a government committing genocide in Gaza, arms its military, shares intelligence, and now refuses to rule out dragging us into another catastrophic war.” Polanski, who has said he thinks the UK should withdraw from Nato, similarly pointed to the lessons of history on this. He added: “We saw in 2003 what happens when a prime minister chooses loyalty to an American president over the will of the British people. They must learn from that shameful chapter in history.”

On Sunday, in a post on X, Polanski said of Starmer’s statement on US strikes: “I don’t think anyone expected him to say anything better.” Polanski added “Iran were negotiating – when Israel launched a war on them. The US joined in – and now our Prime Minister basically says, ‘well they were asking for it.’” Green and Labour party insiders have told me that a Polanski victory in the party’s leadership election in September could potentially lead to the defection of some dissatisfied back-bench Labour MPs. The left-wing commentator, and former candidate for selection as a Labour MP, Grace Blakeley, joined the Green Party earlier this week to vote for Polanski. More could follow if tensions over the war in Iran continue to boil, and Labour politicians and voters find themselves disappointed (or even appalled) by the Prime Minister’s stance.

Privately, though, there is concern from those who are sympathetic to Gaza on the left that this escalation could only lead to more polarisation. Prior to Israel’s strikes on Iran – and Iran’s retaliation – it felt as though opinion on Gaza was on the cusp of a turning point, with more MPs feeling able to speak out about what they saw as indiscriminate Israeli aggression. This new stage of the conflict opens up a new attack line. As Corbyn, Polanski, or other pro-Gaza MPs and politicians call for the end of arms sales to Israel, the worry is that critics will fire back that these MPs would leave Israel defenceless from Iran.

None of this puts the Prime Minister in an easy position. Starmer has already received extensive criticism for being slow to act on sanctions and arms sales. If he aligns the UK with the US on this war, or comes out in direct support of Trump, it will open him up to even further attacks from the left (and could even run the risk of more Labour losses to the Gaza independents or an equivalent organised party in 2029). Memories of Iraq, and the political damage that terrible conflict wrought on the Labour Party have certainly not dissipated; the left is keen that no one forgets.