Bereaved families who lost relatives in a mass drowning in the Channel a year ago have criticised the UK body investigating the tragedy for a lack of progress in determining how and why dozens of lives were lost. An interim report from the Marine Accident Investigation Branch (MAIB) published on Thursday confirmed that the boat had reached UK waters. Initially, officials thought the tragedy was outside their jurisdiction because the bodies and survivors were found in the French part of the Channel. But an investigation into the British search and rescue response was launched in January “when it became evident that some of the events relating to this loss of life had occurred inside UK waters”, the report states. It adds that when officials did send out search and rescue services, there was no sign of the boat or its passengers. In the incident on 24 November 2021, 31 people slowly froze to death in the Channel. They had repeatedly made SOS calls to French and UK emergency services, but no help was sent to them. Of those on board the overcrowded dinghy, 27 bodies were recovered. Four are still missing. Only two people survived in the incident, the worst maritime disaster in the Channel for 30 years. Among the dead were 21 men, seven women, including one who was pregnant, and three adolescents. Their flimsy boat left France at about 10pm on 23 November 2021. Around midnight it began to deflate and sink in the middle of the Channel. When repeated calls were made by the passengers to French and UK emergency services, the French told them they were in British waters while the British told them they were in French waters. It was not until 11 hours later – at 2pm the next day – that a French fisher spotted the bodies in the water and raised the alarm. Speaking through their lawyer on the first anniversary of the tragedy, the families expressed dismay about the interim two-page report from MAIB. Maria Thomas, of Duncan Lewis solicitors, said: “We need to have one independent investigation into what happened that night. The English and French sides should have access to each other’s records from the night of the drownings. If there are systemic issues that contributed to large loss of life that night, these need to be identified in an independent inquiry to ensure that a tragedy like this does not happen again.” Sixteen of the bereaved relatives have written to Rishi Sunak urging him to make changes to prevent future tragedies. In the letter from the bereaved relatives to the prime minister – co-signed by Care4Calais, Channel Rescue and Safe Passage, along with several trade unions including the Trades Union Congress and the RMT, MPs, including Bell Ribeiro-Addy, and the writer Michael Rosen – the families demand justice for their lost loved ones. The letter states: “We demand answers to why French and British authorities failed desperate people who came asking for help. We demand an end to the poisonous rhetoric used by our politicians – calling innocent refugees ‘illegal migrants’ or, worse, ‘an invasion’ – which breeds fear and division. We call for safe passage to allow these refugees to claim asylum in Britain without risking their lives in the Channel.” The bereaved families are further distressed because on Wednesday they received generic letters via text or WhatsApp from MAIB that referred to neither them nor their lost loved ones by name, asking them to provide evidence for the investigation, such as final phone conversations they might have had with their relatives when the dinghy started to deflate. Relatives say they do not understand why it took MAIB a year to make contact with them. Thomas said: “There has been no promptness and no transparency in the legal case the bereaved families are bringing. Promptness is critical because it ensures preservation of evidence, and it is concerning that it has taken this long to contact the families. “Families were sent depersonalised letters without their names or the name of the relative they lost, on the day before the anniversary, making them feel the investigators don’t care about them. This has further eroded their trust in the MAIB investigation.” A spokesperson for the MAIB said: “On the anniversary of the accident, our thoughts are with those who lost loved ones in this tragedy. While it may not be possible to fully understand precisely what happened at the time of the accident, it is important that we examine whether the UK’s emergency response was appropriate that night once it became apparent that migrant boats might be in distress in UK waters. “The purpose of our investigation is to improve safety, and if lessons can be learned, and if deemed appropriate, we will make recommendations to address the issues identified. Our investigation is ongoing, and we expect to publish it in early summer 2023.” The spokesperson added that tracing victims’ families was “a complex process”.