The UK government is being challenged over whether it will join Labour in supporting an international criminal court inquiry into potential war crimes committed by Israel, with the shadow foreign secretary, David Lammy, calling for all parties to uphold international law. The ICC prosecutor, Gen Karim Khan, has insisted he has jurisdiction, but under the premiership of Boris Johnson the government said the court had no legal right to interfere. Both the UK and the US intervened against the ICC becoming involved in Israel in 2021 when, after five years of preliminary inquiry, judges confirmed that Palestine’s status as an occupied territory rather than a sovereign country did not preclude an ICC investigation. In a letter to the Conservative Friends of Israel in April 2021, Johnson reassured pro-Israeli MPs that the government opposed an ICC investigation into alleged war crimes. “We do not accept that the ICC has jurisdiction in this instance given that Israel is not party to the statute of Rome and Palestine is not a sovereign state. This investigation gives the impression of being a partial and prejudicial attack on a friend and ally of the UK’s,” the letter stated. At the same time the Trump administration in the US rejected ICC involvement, insisting “Palestinians do not qualify as a sovereign state and, therefore, are not qualified to obtain membership as a state in, participate as a state in, or delegate jurisdiction to the ICC”. The state department said: “Unilateral judicial actions … exacerbate tensions and undercut efforts to advance a negotiated two-state solution.” The Conservatives have not subsequently said they no longer support the legal analysis set out by Johnson. In August the UK opposed a reference to the international court of justice, the body that arbitrates on inter-state disputes. Writing in the Guardian last week, Khan said: “My office has ongoing jurisdiction in relation to any alleged crimes committed on the territory of the state of Palestine by any party. This includes jurisdiction over current events in Gaza and in the West Bank. “Israel has clear obligations in relation to its war with Hamas: not just moral obligations, but legal obligations that it has to comply with the laws of armed conflict. These laws are clearly outlined in the Rome statute and the Geneva conventions.” Lammy said in a statement on Sunday night that “all parties must uphold international law”. “Allegations of breaches of international humanitarian law should always be treated with utmost seriousness,” he said. “Assessing specific allegations is the proper task of lawyers and competent international courts. Labour supports the independence of the international criminal court and recognises its jurisdiction to address the conduct of all parties in Gaza.” In his statement the Labour MP for Tottenham continued to edge away from support simply for short humanitarian pauses, saying “a full and immediate pause” is required, though he did not specify a length. The former Labour foreign secretary David Miliband called for an initial five-day pause last week. Lammy is working to prevent a damaging backbench rebellion next week, when an SNP amendment calling for a ceasefire will be voted upon. Lammy said “short pauses are a first step but on their own won’t make the impact needed to relieve this humanitarian crisis. The damage to water pipelines and other infrastructure to hospitals need to be rebuilt, and that requires a longer pause. The aid getting into Gaza is still completely insufficient. It is unacceptable that Israel still has not lifted the siege conditions. “We need a full and immediate humanitarian pause in the fighting across the whole of Gaza to alleviate the suffering of Palestinian civilians and for Hamas terrorists to release the hostages. The full pause must start now to get sufficient food, water, electricity, medicine and fuel into Gaza and address the ongoing humanitarian catastrophe. “Far too many Palestinian civilians and children have been killed and there has been far too much civilian suffering over the past month. Hamas must release the hostages and stop using civilians as human shields and Israel must take urgent, concrete steps to protect civilians.”