Rishi Sunak has called for an urgent investigation into the deaths of three British aid workers who were killed by an Israeli airstrike that hit an aid convoy in Gaza, as reports of the victims’ names emerged on Tuesday evening. The Guardian understands two of the three were 33-year-old James Henderson, a former Royal Marine from Cornwall, and John Chapman, a 57-year-old father of two who reportedly previously worked for the Special Boat Service. The BBC named the third Briton as James Kirby. Sunak said far too many aid workers and ordinary civilians had lost their lives in Gaza during a conversation with Israel’s prime minister, Benjamin Netanyahu, on Tuesday. David Cameron, the foreign secretary, spoke to his Israeli counterpart, Israel Katz, and requested an urgent explanation of the incident. A Downing Street spokesperson said the prime minister “was appalled by the killing of aid workers, including three British nationals, in an airstrike in Gaza … and demanded a thorough and transparent independent investigation into what happened”. The spokesperson added: “The prime minister said far too many aid workers and ordinary civilians have lost their lives in Gaza and the situation is increasingly intolerable. “The UK expects to see immediate action by Israel to end restrictions on humanitarian aid, deconflict with the UN and aid agencies, protect civilians and repair vital infrastructure like hospitals and water networks. “The prime minister reiterated that Israel’s rightful aim of defeating Hamas would not be achieved by allowing a humanitarian catastrophe in Gaza.” In a post on X, Lord Cameron said he underlined to Katz that the deaths of the humanitarian workers were “completely unacceptable” and that Israel must make “major changes to ensure safety of aid workers on the ground”. Andrew Mitchell, a Foreign Office minister, summoned the Israeli ambassador over the incident and requested “a quick and transparent investigation, shared with the international community, and full accountability”. The group of aid workers had been travelling in two armoured vehicles marked with the charity’s logo, according to a statement released early on Tuesday. WCK said those killed were from the UK, Australia, Poland and Palestine, as well as a US-Canada dual citizen. The charity said it was suspending operations in the Palestinian territory. Earlier, Sunak told broadcasters during a visit to north-east England on Tuesday morning: “We are asking Israel to investigate what happened urgently, because clearly there are questions that need to be answered. “My thoughts are with [the victims’] friends and family,” the prime minister added. “They are doing fantastic work bringing alleviation to the suffering that many are experiencing in Gaza.” Keir Starmer condemned the strike and called for a full investigation and immediate ceasefire. “Reports of the death of British nationals – among others from World Central Kitchen – in an Israeli strike on Gaza are horrifying,” the Labour leader said. “Our thoughts are with the families of all of those killed. This war must stop now. Far too many innocent people have died in this conflict and more than a million are facing starvation.” The Foreign Office said it was working to support the families. Netanyahu said the aid workers were killed by an “unintended strike” by Israeli forces. The head of the Norwegian Refugee Council, Jan Egeland, told BBC Radio 4’s World at One: “This is a war machine totally out of control in Gaza.” He said more aid workers had been killed there “than in any other conflict”. Egeland said he had visited Gaza recently and ate meals with the WCK. “There is no nobler task,” he said. “I saw the good work of these very compassionate people helping the civilian population.” Alicia Kearns, the Tory MP who chairs the UK’s foreign affairs select committee, said: “Humanitarian agencies must be given the assurances they need that their people will be protected.” UK-based aid agencies have condemned the strike. The UK-based charity Medical Aid for Palestinians said it was a “horrific attack” that demonstrated there was “no safe place in Gaza, whether you are Palestinian, British or any other nationality”. It added: “Gaza is one of the most dangerous places in the world to be an aid worker right now.” The Israel Defense Forces “expressed the deepest condolences” to the families of the aid workers and said it was “reviewing the incident at the highest levels”. “As a professional military committed to international law, we are committed to examining our operations thoroughly and transparently,” an IDF spokesperson said. “The incident will be investigated in the fact-finding and assessment mechanism, an independent, professional and expert body.”