One person has died and another is in a life-threatening condition after a boat carrying migrants partially deflated in the Channel.
More than 60 people were on board the boat, which got into trouble about 8km (5 miles) from the French coast, according to the French coastguard.
A group of 66 survivors was taken to Calais, where the injured person is being treated in hospital.
The French coastguard said two other people may still be missing.
One female casualty could not be resuscitated and a second person was flown by helicopter to a Calais hospital in a life-threatening condition, the French coastguard said.
A spokesperson said no other people had been found in the search for survivors.
Searches are continuing by air and sea, they said.
A spokesperson for Prime Minister Rishi Sunak said: “Thoughts are with all those affected”.
They added the incident “serves as a stark reminder of how dangerous these crossings are.”
French officials said they reached the boat at 01:15 local time (00:15 GMT), finding that one of the boat’s tubes was deflated and there were people in the water.
Two of the rescued migrants were found unconscious, with one in a life-threatening condition evacuated by helicopter to a Calais hospital.
The other could not be resuscitated.
The others on the boat were taken to Calais for treatment, and the coastguard said sea and air searches would continue.
The rescue occurred a few miles off the French coast near Grand-Fort Philippe, 20km east of Calais.
Enver Solomon, chief executive officer of the Refugee Council, said: “This is yet another terrible and avoidable tragedy.
“These appalling deaths are becoming too common and there is an urgent need to put in place safe routes so people don’t have to take dangerous journeys across the world’s busiest shipping lane.”
Home secretary James Cleverly said in a post on X: “The incident in the Channel last night is a horrific reminder of the people smugglers’ brutality. 25,000 people have been averted from crossing this year – but we must and will do more.
“Every boat stopped is a potential life saved.”
It was the first attempted crossing for 11 days due to windy weather in the Channel.
But 730 people made the journey in the first three days of December when the sea was calm.
So far this year more than 29,000 people have reached the UK in small boats – though this represents a fall of about a third on the same period last year.
The UK government has said that “stopping the boats” crossing the English Channel is a key political priority.
As part of this, it is pushing ahead with a plan to send some asylum seekers to Rwanda, despite the Supreme Court ruling that the policy is unlawful.
The English Channel is one of the most dangerous and busiest shipping lanes in the world, with 600 tankers and 200 ferries passing through it every day.
French authorities confirmed two people had died in a similar incident off the coast of France last month.
In August, at least six people died after a boat carrying migrants sank off the French coast.
In November 2021, at least 27 migrants died after a dinghy sank while heading to the UK from France, the highest recorded number of deaths from a single incident.