Five migrants trying to cross the Channel have died in French waters, a French maritime official told the BBC.
Around 70 people were trying to get into a small boat attempting to launch from a beach when it overturned in the early hours of Sunday morning.
Dozens were pulled from the water during overnight rescue efforts in Wimereux, to the south of Calais.
Foreign Secretary David Cameron told the BBC that the incident was “heartbreaking”.
One person remains in a critical condition after being transferred to a hospital in nearby Boulogne-sur-Mer, and one person suffered non-life threatening injuries.
Another 32 people were unharmed.
An investigation has been launched by the Boulogne-sur-Mer public prosecutor’s office into “aggravated manslaughter”.
Jacques Billant, prefect of the Pas-de-Calais region, told reporters criminal networks were endangering migrants.
“Going out to sea in 7C water means going to your death. With a lifespan limited to 10 minutes in the event of capsizing,” he said.
“Unfortunately, that’s what happened”.
He added that post-mortem examinations would determine the cause of death which may be due to “drowning” or “thermal shock”.
People got into trouble almost immediately after the boat departed the French coast for England at around 02:00 local time (01:00 GMT) on Sunday.
Dozens were trying to board the vessel as it left the beach and found themselves in difficulty at sea, the French maritime prefecture said.
A tugboat patrolling the coast attended the scene and found the bodies.
Around 50 firefighters and several police vehicles were deployed to help with several boats and a French Navy helicopter also helping, according to regional newspaper La Voix du Nord.
Survivors were taken to a local community centre.
The UK Coastguard had no involvement as the incident occurred in French waters very close to the beach near Wimereux.
Enver Solomon, chief executive of the Refugee Council, said the Channel deaths “must be a wake-up call to take decisive action” – including the provision of safe routes for those fleeing war-torn countries.
The deaths came several days after the first small boat crossing of the year was recorded.
It follows a nearly four-week period up to 12 January when no Channel crossings were recorded, which the Home Office says was due to poor weather conditions.
In the same period 12 months earlier, 503 migrants were detected in the Channel.
The provisional total for 2023 – 29,437 crossings – is down on the 45,774 recorded for 2022, which is the highest number since figures began to be collected in 2018.
Speaking to the BBC’s Laura Kuenssberg on Sunday, Lord Cameron said it was “heartbreaking” to hear more lives had been lost in Channel waters.
He said the British government had done “a huge amount” to support French authorities with policing and intelligence operations.
And he insisted that passing the UK government’s Rwanda bill – which aims to send some asylum seekers to the African country – was “essential” to save lives and stop people crossing the Channel on small boats.
The bill is designed to discourage migrants from trying to cross the Channel in small boats.
Tory MPs are piling pressure on Prime Minister Rishi Sunak over the bill, which Mr Sunak is trying to revive after the Supreme Court ruled the earlier scheme was unlawful.
Speaking on the same programme, Labour leader Sir Keir Starmer said the incident was a “tragic loss of life” and added: “I absolutely agree we need to stop these Channel crossings”.
But the Labour leader rejected the “gimmick” of the Rwanda scheme, saying the UK should “go after the criminal gangs that are running this vile trade [of boat crossings]”.
Separately, a French report earlier this month stated that the UK was not passing on enough information about small boats crossing the Channel.
According to the Court of Accounts, which audits spending in France, intelligence provided to French police was often “first level” and “very general”.