LILLE, France (AFP) - Seventy-one migrants were intercepted on several boats in the English Channel overnight, with some needing hospitalisation for hyperthermia, French and British authorities said on Thursday (Dec 26).

French sea rescuers received an alert in the early morning hours of a boat transporting 14 migrants who needed rescuing.

They were found in a state of hyperthermia and brought to a hospital in Boulogne-sur-Mer in northern France, joining eight others admitted a short while earlier, regional officials said.

The eight had taken to sea, trying to make their way to Britain, but turned back when their boat was spotted by patrollers.

British authorities, for their part, said they had rescued 49 people, including a minor, on four other boats overnight.

Over the past year, growing numbers of migrants from Africa, the Middle East and Central Asia have taken to the treacherous waters of the Channel in small fishing boats or inflatable dinghies.

Rights groups have linked the crossings to a police crackdown in Calais in northern France, which has made it harder for migrants to set up camp there.

Hundreds of migrants try to enter Britain annually through the world's busiest waterway using unsafe boats.

At least four migrants have died so far this year attempting to make the dangerous crossing in the Channel, with its strong currents and very cold waters.