French, Belgian and British helicopters were used to search for and rescue nine more migrants in a dinghy.

The group included a woman and child and two of the victims suffered hypothermia.

Now French maritime officials have given a stern warning about sailing in dinghies in the rough Channel in winter, particularly with children.

It is the latest in a series of incidents involving migrants trying to reach Britain in the last couple of months, usually by dinghy.

Since November 8, there have been 20 incidents involving a total 171 people.

This group was found near Dunkirk and brought to safety last night after a three-hour hunt.

The French Channel maritime authority Préfecture Maritime de la Manche et de la Mer du Nord said that a distress signal had first been sent out at 10.40pm yesterday.

Helicopters from the French navy, the British HM Coastguard and Belgium joined search and rescue vessels to find the dinghy.

The rescuers at first struggled to find the dingy in the pitch darkness but were further guided by another distress call.

It was at 12.35am that British and Belgian helicopters were brought to join the French aircraft in the air search.

The dinghy was finally located 30km (19 miles) north-west of Dunkirk at 1.45am.

The nine on board were transferred to the port of Dunkirk where they received medical attention and were taken in by police.

A spokesman for the French maritime prefecture said: "In this winter season characterized by low temperatures and bad weather at sea, the risks of hypothermia and the possibility of a reversal of boats caused by strong waves are particularly significant.

"Migrants who plan to cross the English Channel at this time of year risk their lives even more.

"The maritime prefect also calls for the responsibility of the adults who, in attempting these crossings, take undue risks for themselves and for the children present in the boats."