PARIS, Aug 12 (Reuters) - A group of around 40 migrants was rescued on Thursday after the dinghy in which they set out to reach Britain began to sink, French authorities and one of the fishermen who saved them said. Record numbers of migrants are crossing the Channel between France and Britain, often on overloaded rubber dinghies that barely stay afloat. The currents are strong and commercial ship traffic is heavy. read more One person, who was unconscious and suffered heart failure, was airlifted to a hospital in Calais, French authorities said. All the others on board, rescued by two fishing boats and French and Belgian sea and air units, were safely brought to the French port of Dunkirk, its prefecture said in a statement, adding that other rescue operations were still under way.Nicolas Margolle, captain of the Nicolas Jeremy trawler, said his crew rescued four Eritrean men who had fallen into the cold sea. "The dinghy was sinking," Margolle told Reuters. "The shipwrecked men were in hypothermia and very weak, they said they had been in the water for over three hours." His crew gave them warm clothes, water and food. They stayed onboard for about an hour before being brought back to Dunkirk by the French navy. "The Nicolas Jeremy crew was proud to have helped them but also in shock. Many of these people have travelled thousands of kilometres and are willing to risk their lives to go to England," he said. After being taken to safety and receiving medical treatment, the migrants were expected to be set free and offered shelter.Britain says it wants to make the country less attractive to asylum seekers. Under proposed legislation, those trying to enter illegally would face up to four years in prison. In July, the French and British governments announced they planned to intensify efforts to intercept vessels and stop boats making the perilous voyage. read more