The family of James Kirby, a World Central Kitchen aid worker killed in Gaza, have called for an independent investigation into his death and said neither British nor Israeli diplomats had been in touch, even though an internal Israeli inquiry said his death had been a tragic accident. Kirby was among seven aid workers, including Britons John Chapman and James Henderson, who were killed when an Israeli airstrike targeted their clearly marked vehicle on 1 April. The Israeli inquiry led to the dismissal of two officers. The statement was issued by Kirby’s cousin Louise on behalf of his family on the day of his memorial service in Bristol Cathedral. Describing his death as a diabolical tragedy and a murder, the family said they were “still struggling to find answers and accountability for what happened”, pointing out the aid workers were travelling in a vehicle for which clearance had been given for them to carry out humanitarian work. “The State of Israel says the murder was an accident. So we were surprised not to have had any contact or condolence from Israel’s ambassador to the UK in London or from any Israeli official,” the statement said. “There must be a proper independent inquiry into the attack on innocent aid workers and for the evidence to be assessed if appropriate by a relevant court.” The family say they have had no contact from the UK government since the aid workers’ deaths or received “any evidence whether a credible independent investigation is taking place or the results of any investigation if it has taken place”. Kirby, 47, a former serviceman, was providing security for the convoy moving food to a warehouse in Gaza. World Central Kitchen (WCK) was at the forefront of efforts to create a maritime aid corridor from Cyprus. An inquiry by the Israel Defense Forces (IDF) found a drone operator mistakenly targeted the convoy after thinking it had been taken over by Hamas gunmen. Three missiles were fired in three locations over five minutes. The first hit a car and some passengers escaped to another vehicle. That was then hit by a second missile. Some survivors tried to flee in a third car that was also struck. Everyone in the convoy was killed. As well as the three Britons, the Australian national Lalzawmi Frankcom, Polish national Damian Sobol, Palestinian Saifeddin Issam Ayad Abutahas and US-Canadian citizen Jacob Flickinger were also killed in the strike. After its internal investigation, the IDF sacked two officers and formally reprimanded two senior commanders. The inquiry found that a plan setting out WCK’s movements, which had been agreed with the IDF, was not given to the drone unit that attacked the convoy. It also concluded that evidence of an armed man in the convoy was insufficient to justify targeting it. The drone operators kept firing on the convoy after the initial strike. The evidence from the investigation was passed to the military advocate general – the Israeli army’s top legal authority – to determine if there had been any criminal conduct. No further action has been announced. The family says this is not just about them but about how families are treated. “Just saying ‘sorry it was an accident ‘is not enough’. We need to know there has been accountability at all levels so that it does not happen again,” the statement said. Poland’s deputy foreign minister, Andrzej Szejna, has demanded a criminal inquiry. WCK has also called for an independent investigation, saying: “The IDF cannot credibly investigate its own failure in Gaza.” A UK government spokesperson said the bereaved families were being assisted by police liaison support officers, who were in “regular contact” with the Foreign Office. “The death of James and his fellow aid workers was horrific and our thoughts remain with their families,” the spokesperson said. “Attacks on aid workers are never justified, and we remain fully committed to their protection as they support some of the most vulnerable people in the world.”