Migrants picked up at sea while attempting to cross the English Channel, are escorted off from the UK Royal National Lifeboat Institution (RNLI) lifeboat at the Marina in Dover, southeast England, on December 14, 2022.

London (AFP) - A teenager was among the four people who died after a small boat packed with migrants capsized in freezing temperatures in the Channel, a regional official said on Thursday.

Britain’s coastguard and other emergency responders, as well as a fishing boat in the area early Wednesday, plucked 43 people from the frigid waters of one of the world’s busiest shipping lanes.

However four of those retrieved from off England’s south coast during the large-scale rescue operation, which continued until mid-afternoon Thursday, did not survive, UK officials have confirmed.

The leader of the council in Kent, southeast England – home to the stretch of coastline where most cross-Channel migrants arrive – told colleagues at a cabinet meeting that one of the victims was a teenager.

A UK Royal National Lifeboat Institution (RNLI) lifeboat arrives at the Marina in Dover, southeast England, on December 14, 2022.

Conservative councillor Roger Gough also said that 12 of the 39 people who survived were lone migrant children who have now been taken into the council’s care, UK media reported.

He called the tragedy a “sobering reminder of the human costs of what is an ongoing crisis”, the reports said.

The UK interior ministry could not confirm the details, noting it would be for a coroner to formally confirm details of those who died.

The tragedy comes just over a year after at least 27 people died in the Channel in another incident.

A higher death toll appears to have been averted thanks largely to the crew of the fishing trawler Arcturus, who discovered the dozens of migrants clinging to stricken inflatable vessels and in the icy waters.

Forensics police officers arrive at the marina in Dover, southeast England, on December 14, 2022 to inspect the bodies of migrants believed to be kept inside a tent (L) outside the UK Royal National Lifeboat Institution (RNLI) office after they died overnight while attempting to cross the English Channel.

“It was like something out of a Second World War movie, there were people in the water everywhere, screaming,” the boat’s skipper Raymond Strachan told Sky News.

“I steamed towards the dinghy and we secured it with a rope to the side of the boat. We were trying to pull them off the dinghy.”

The crew are believed to have saved 31 of the 39 people rescued during the hours-long operation.

On Thursday evening, migrants rights groups in northern France were set to hold a rally in memory of the deceased.

It would also “denounce the policies at the border which are once again responsible for the deaths of people in exile,” organisers said.

In a joint statement issued late Wednesday, French Interior Minister Gerald Darmanin and British counterpart Suella Braverman said the incident was “a stark reminder of the urgent need to destroy the business model of people-smugglers”.

The UK government is trying to pass new laws to prevent the record numbers of migrants from attempting the Channel crossing, including making any such arrivals inadmissible for asylum claims.