Five people have died and a sixth is in a critical condition after getting into difficulty in icy waters trying to reach the UK from northern France, the French maritime authority has said. Four people were found dead in the early hours of Sunday morning, while the body of a fifth victim was found by a walker at about 9am. The victims were part of a group of more than 70 people attempting to board boats off the seaside resort of Wimereux on Sunday, according to local media reports. In all, 72 people were rescued overnight, with 20 suffering advanced hypothermia, including two young children and one pregnant woman taken for urgent care in Boulogne. La Voix Du Nord reported that among those rescued from the drowning incident was a one-month-old baby. The maritime prefecture for the Channel region in northern France said it had received reports of a boat in difficulty near the beach in Wimereux at 1.45am (0045 GMT). Security officials near the area rescued those closest to the shore and at 2am “three unconscious people were spotted at sea”. At 2.15am a French navy helicopter arrived from Le Touquet while a fourth unconscious person was spotted by the Abeille Normandie patrol boat and winched up by the helicopter. “Two other people in a worrying state of health were also rescued on the beach by the internal security forces,” the statement added. One of them was unconscious and taken to Boulogne-sur-Mer hospital while the second person was in severe hypothermia. A large surveillance team continued working through the night and at about 8.45am a fifth person was found dead on the shore by a walker, the prefecture said of the first reported deaths crossing the Channel since 15 December. More than 30 people were treated by emergency services. One person, who spoke on condition of anonymity, had said about 70 people were brought in at about 3am, including “entire families with children, some of them very young”. “Some of the survivors did not stay and told us they wanted to go to the Dunkirk train station to reach an accommodation centre in Armentières,” the source told the Agence France-Presse news agency. Authorities have launched an investigation into “aggravated manslaughter” and other crimes, the Boulogne-sur-Mer public prosecutor’s office said. The first four people found dead were identified as Iraqi and Syrian, according to local media. La Voix du Nord reported that hundreds of people had sought to take advantage of weaker winds to try to reach the UK, despite the sub-zero air temperatures and 9C (48.2F) water. UK Home Office figures published on Sunday revealed that 124 refugees and migrants crossed the Channel in three boats on Saturday, the first crossings for 27 days. Poor weather is believed to be a contributory factor in the large gap in crossings in recent weeks. David Cameron, the UK foreign secretary, said the deaths showed how urgent it was to break the people-smuggling business model. “It breaks my heart, but it just shows we’ve got to stop the boats, we’ve got to stop this illegal trade in human beings,” he said. The opposition leader, Labour’s Keir Starmer, described the incident as “just awful” and said more must be done to stop criminals exploiting people. “I refuse to accept that somehow these gangs are untouchable, and we can’t do anything about it,” he told the BBC. A spokesperson for the humanitarian organisation Utopia 56 said: “We cannot imagine the level of pain and suffering created by these situations. Why do we let people die when we could actually build solutions, why are political responsibilities never pointed at?” Enver Solomon, the chief executive of the Refugee Council, said he was “deeply saddened by the terrible loss of life” and that the deaths must act as a “wake-up call” for the UK government to “take decisive action and reduce dangerous Channel crossings by providing safe routes for those fleeing war-torn countries or repressive regimes”. A 36% fall in the number of Channel crossings in 2023 has coincided with a 30% increase in deaths among asylum seekers in northern France waiting to cross – with 23 deaths in 2023. One French NGO said that continued evictions from makeshift camps around Calais and Dunkirk would push more people into making the treacherous journey cross the Channel.