Migrants were rescued from a second sinking boat on the same night four people died in the Channel this week.
Border Force officers rescued 50 people, five of whom had ended up in the freezing water, after their boat started to sink just hours before a major search-and-rescue operation was launched when a dinghy capsized.
Detectives from Kent Police, alongside the National Crime Agency (NCA) are already investigating the dinghy accident in the early hours of Wednesday that left four dead and 39 people needing to be rescued, amid reports that those on board paid thousands of pounds to people- smugglers.
Officers are trying to identify the people who died and track down their relatives, the force said.
The rescue effort began around 2.15am, according to the Home Office.
But now it has emerged that a separate search-and-rescue mission was launched earlier that morning, at around 12.30am.
Coastguard crews, Border Force officials, the Navy and French rescuers joined forces for that operation.
A spokesman for the Maritime and Coastguard Agency said: “HM Coastguard coordinated a search-and-rescue response to an incident involving a small boat off Kent at 12.30am on Wednesday, 14 December, working with the Navy, Border Force and other partners.
“We sent Border Force vessel Volunteer, supported by two French vessels.
“HM Coastguard will continue to safeguard life around the seas and coastal areas of the UK, working with search and rescue resources in the area.”
Migrants on board the second boat told fishermen they had paid £5,000 each to people-smugglers for the journey from France to the UK, according to media reports.
Earlier this week, Prime MinisterRishi Sunak announced more funding for the NCA – Britain’s version of the FBI – to tackle organised immigration crime in Europe.
NCA director-general Graeme Biggar said: “This incident, tragically, highlights the dangers of these crossings, a high percentage of which are facilitated by organised criminal networks.
“They treat people as a commodity to be profited from and think nothing of putting them in incredibly dangerous situations. Working with our partners on both sides of the Channel we are determined to find those responsible and bring them to justice.”
The NCA is also involved in the French probe into the deaths of at least 27 migrants in the Channel last year.
