Four migrants who tried to reach Britain died in the night from Thursday to Friday after their boat capsized in the Channel, a French coast guard spokesperson said on Friday, confirming earlier media reports.

A total of 67 people were aboard the boat off the coast of Boulogne-sur-Mer in northern France, the spokesperson said, adding that 63 of them were rescued by an operation involving four ships and one helicopter.

Several thousand people have arrived in Britain this year via small, overloaded boats - usually flimsy inflatable dinghies - that risk being lashed by the waves as they try to reach British shores.