Boris Johnson has said banning arms sales to Israel would be “insane”. The former prime minister also criticised the foreign secretary, David Cameron, for remaining silent on the debate over curtailing UK arms sales to Israel. The Israeli Defense Forces (IDF) launched airstrikes on Monday, killing three British aid workers associated with the World Central Kitchen (WCK). In the aftermath, MPs from all major political parties have called on the government to end arms trading with Israel. The same sentiment was expressed in a letter signed by more than 600 lawyers, including former supreme court justices. Israel claimed the strike was not deliberate, describing the attack on the aid convoy as a “grave mistake stemming from a serious failure”. Israel officials have since dismissed two officers involved in the strikes. In a scathing column in the Daily Mail, Johnson wrote that the attacks on the WCK convoy were “shattering” but then defended Israel, claiming it was sending warnings of the IDF’s attacks, which are “trying to use precision munitions”. Johnson added: “If the west continues to crumble – and especially if Britain and the US crumble – then the Israelis will be prevented from getting into Rafah. They will be prevented from achieving their objective: of finishing Hamas as a military force in Gaza.” He added: “Is that really what you want, all you legal experts who say that Israel’s actions now necessitate an arms embargo? Do you want to hand victory to a bunch of murderers and rapists? We are being asked to shun the Israelis, to mount a total moral repudiation of Israel – when that country has only recently suffered the biggest and most horrifying massacre of Jewish people since world war two.” Johnson added that if Hamas released its hostages, it would “mean the immediate withdrawal of the Israeli Defense Forces and the end of the conflict”. Johnson concluded that banning arms sales to Israel would be “insane” and “shameful”. “The sooner the government formally denounces the idea, the better,” he said. Cameron said the government would review the IDF’s report, which was released on Friday, but stopped short of coming down on either side of the debate. Johnson wrote that Cameron has “gone into a kind of purdah on the subject”. Cameron said: “Lessons must be learnt from today’s initial findings from the IDF. It’s clear major reform of Israel’s deconfliction mechanism is badly needed to ensure the safety of aid workers.” The Labour leader, Keir Starmer, is also facing mounting pressure to back an arms embargo after the London mayor, Sadiq Khan, stressed the need for the government to take immediate action. Alicia Kearns, the Conservative chair of the foreign affairs select committee, has been more forthright, stating that it was “devastating” that it had taken six months and the deaths of western aid workers for Israel to change their approach to supplying international humanitarian aid”. The US president, Joe Biden, has reportedly written a letter to leaders in Egypt and Qatar calling for help to broker a deal with Israel and Hamas over the release of more hostages. Biden is also facing pressure to halt arms to Israel. More than three dozen congressional Democrats, including the former House speaker Nancy Pelosi, have signed a letter to the president and the secretary of state, Antony Blinken, calling for a halt to weapons transfers to Israel.