The small boat got into difficulties in the English Channel in the early hours, say coastguards.
People are feared to have died after a small migrant boat ran into difficulties in the early hours in the English Channel near Kent.
The BBC’s Simon Jones said it was understood there had been deaths but authorities have not confirmed them.
The major search and rescue operation was launched in UK waters in freezing conditions after reports of an incident at about 03:40 GMT.
The coastguard, the French Navy and an air ambulance were sent to help.
A fishing boat, which was also in the area, helped with the rescue.
HM Coastguard helicopters from Lydd and Lee on Solent were also involved.
South East Coast Ambulance Service said it was called following reports of the incident, and sent crews to Dover, in Kent, to help with the rescue efforts.
The government said it was aware of the incident and agencies were supporting the coordinated response.