More than 20 people have died after their boat sank in the English Channel, French media has reported.

France’s prime minister said the shipwreck on Wednesday was a “tragedy” and his thoughts were with “victims of criminal smugglers who exploit their distress and injury”.

French politician Franck Dhersin said a boat with more than 50 people aboard had sunk in the middle of the Channel, according to the Press Association.

Mr Dhersin said on Twitter that at least 24 people had died in the capsizing while others had survived.

A rescue operation is under way in the Channel by air and sea as French and British authorities search for anyone still in the water.

The emergency search was sparked when a fishing boat sounded the alarm earlier on Wednesday after spotting several people at sea off the coast of France.

French prime minister Jean Castex said: “My thoughts are with the many missing and injured, victims of criminal smugglers who exploit their distress and injury.”

French interior minister Gerald Darmanin confirmed on Twitter that people had died but did not give a number.

Dover MP Natalie Elphicke said: “This is an absolute tragedy. It underlines why saving lives at sea starts by stopping the boats entering the water in the first place.

“As winter is approaching, the seas will get rougher, the water colder, the risk of even more lives tragically being lost greater.

“That’s why stopping these dangerous crossings is the humanitarian and right thing to do.”

A number of people are also believed to have reached Britain in small boats on Wednesday, with people seen being brought ashore in Dover by immigration officials.

The Dover Strait is the busiest shipping lane in the world and has claimed many lives of people trying to cross to Britain in inflatable dinghies.

More than 25,700 people have made the dangerous journey to the UK in small boats this year – three times the total for the whole of 2020, according to data compiled by the PA news agency.