The Israeli government’s “killing rage” in Gaza poses a threat to the country’s moral and legal authority and will fuel conflict for another 50 years, the former UK defence secretary Ben Wallace has warned. In an intervention that goes further than any other front-rank British politician in its criticism of Israel’s methods in the war, the senior Conservative MP wrote in the Daily Telegraph: “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.” He also criticised Israel’s new generation of “bull in a China shop” politicians for “crashing from one crisis to another”. International pressure on Israel has been growing over the scale of civilian casualties in Gaza. About 19,000 people have been killed in the course of the Israeli offensive, according to health officials in the Hamas-run territory, since the Hamas attack on Israel of 7 October, which killed 1,200 people. At the weekend the UK foreign secretary, David Cameron, joined his German counterpart in calling for a “sustainable ceasefire” in the territory, adding that “too many civilians have been killed”. Grant Shapps, the current defence secretary, said the approach would mean “hostages released, rockets stop flowing and there’s actually a political process in place to make sure that we get to the day after”. The US defence secretary, Lloyd Austin, is due to meet the Israeli prime minister, Benjamin Netanyahu, and the defence minister, Yoav Gallant, this week to discuss in detail when and how Israeli forces may carry out a new phase of fighting. American officials envision smaller groups of elite forces who would move in and out of population centres in Gaza, conducting more precise, intelligence-driven missions to find and kill Hamas leaders, rescue hostages and destroy tunnels, US officials said. The UN security council is also due to vote on Monday on a resolution for a durable and sustainable cessation of hostilities. Cameron defined sustainable as one in which Hamas could not mount further attacks on Israel that threatened its security. In his Telegraph article Wallace was less interested in the timing of a ceasefire than Israel’s tactics. He wrote: “We are entering a dangerous period now where Israel’s original legal authority of self-defence is being undermined by its own actions. It is making the mistake of losing its moral authority alongside its legal one. “I am sure that the shame Benjamin Netanyahu feels for not foreseeing the October 7 attacks is deep, especially for someone who presented himself as a security hawk and tough guy. But perhaps that shame is driving him to lose sight of the long term. “If he thinks a killing rage will rectify matters, then he is very wrong. His methods will not solve the problem. In fact, I believe his tactics will fuel the conflict for another 50 years. His actions are radicalising Muslim youth across the globe.” He urged Israel to be more patient and to cultivate moderate Palestinian voices. An Israeli government spokesperson, Eylon Levy, told the BBC Wallace’s choice of words were “unfortunate language” and that Israel was targeting those who carried out the 7 October attack and was putting in place “unprecedented measures to get civilians out of harm’s way”. Levy said: “What will radicalise a new generation is if the terrorists who burned people alive, and tortured children in front of their parents, and raped Israeli women and girls, literally get away with murder.”