Keir Starmer has joined Rishi Sunak in calling for a sustainable ceasefire in Gaza, as the political rhetoric continues to shift away from unqualified support for Israel’s assault in line with moves from the US and others. Some senior Conservatives were even more explicit. Ben Wallace, a former defence secretary, said Israel’s “killing rage” risked it losing international support, and Alicia Kearns, who chairs the Commons foreign affairs committee, said she believed Israel had broken international humanitarian law. The Labour leader said there was a need “to get to a sustainable ceasefire as quickly as possible”, beginning with a pause in the fighting during which the remaining hostages seized by Hamas on 7 October can be freed and aid can enter Gaza. “It will have to be a political process, to a two-stage solution which, in the end, is the only way that this is going to be resolved,” he said. The prime minister earlier said Israel had a right to defend itself following Hamas’s massacre of Israeli civilians, but “it must do that in accordance with humanitarian law”. “It’s clear that too many civilian lives have been lost and nobody wants to see this conflict go on a day longer than it has to,” Sunak said. “And that’s why we’ve been consistent – and I made this point in parliament last week – in calling for a sustainable ceasefire, whereby hostages are released, rockets stopped being fired into Israel by Hamas and we continue to get more aid in.” Asked to elaborate on the meaning of a sustainable ceasefire, Sunak’s official spokesperson said it did not mean a demand for Israel to stop its assault on Gaza immediately. “We do not believe that calling right now for a general and immediate ceasefire, hoping it somehow becomes permanent, is is the way forward. We need the right conditions to ensure that it lasts as long as possible,” he said. Asked if the prime minister agreed with Wallace’s comments, made in an article for the Daily Telegraph, however, the spokesperson did not reject the former defence secretary’s view. “We are concerned, as we have set out before, that too many civilians are being killed in Gaza and that their vital infrastructure is being destroyed,” he said. In a strongly worded article, Wallace said he agreed with Israel’s right to self-defence but that this did not come without limits: “Going after Hamas is legitimate, obliterating vast swathes of Gaza is not. Using proportionate force is legal, but collective punishment and forced movement of civilians is not.” The Israeli prime minister, Benjamin Netanyahu, was at fault for missing warnings about the Hamas attack, Wallace wrote: “But if he thinks a killing rage will rectify matters, then he is very wrong. His methods will not solve this problem. In fact, I believe his tactics will fuel the conflict for another 50 years.” Kearns echoed the point, speaking to BBC Radio 4’s World At One: “Hamas is an ideology which recruits into its membership. Bombs don’t obliterate an ideology and neither can a stable state be constructed from oblivion.”