Channel migrant deaths: What do we know so far?

At least 27 people have died after a boat headed for the UK capsized in the English Channel. Here's what we know.

A fishing boat sounded the alarm on Wednesday afternoon after spotting several people at sea off the coast of France.

French Interior Minister Gerald Darmanin earlier said 31 migrants drowned, including five women and a young girl.

The total was later revised down to 27.

Mr Darmanin said the boat had 34 people on board. Two people were rescued and one person is still missing.

He said four traffickers linked to the incident had been arrested.

Two people have already appeared in court and an an investigation into aggravated manslaughter has been opened by prosecutors, he added.

French and British authorities were conducting a rescue operation by air and sea.

Mr Darmanin described the boat the migrants were using as a dinghy and "very frail".

He said "it was like a pool you blow up in your garden", according to a translation on Sky News.

French police say the boat set out from the Dunkirk area, east of Calais.

Fishermen in the area said calm weather had prompted more migrants than usual to attempt to make the crossing on Wednesday.

There are reports that about 25 boats had attempted the crossing during the day.

The International Organization for Migration said the incident amounted to the biggest single loss of life in the Channel since it began collecting data in 2014.

UK Prime Minister Boris Johnson chaired a meeting of the government's Cobra civil contingencies committee in the evening.

He said he was "shocked, appalled and deeply saddened" and vowed to leave "no stone unturned" to stop human trafficking gangs.

French President Emmanuel Macron said he would not allow the Channel to become a "cemetery" and vowed to find out who was responsible.

Mr Johnson and Mr Macron spoke on Wednesday night. Downing Street said they agreed on the importance of close working with neighbours in Belgium and the Netherlands, as well as other European countries, to tackle the problem before people reach the French coast.  

French Prime Minister Jean Castex said the incident was a "tragedy" and those who died were victims of "criminal smugglers".

French Interior Minister Gerald Darmanin said the authorities wanted to work with the UK to tackle the issue.

Speaking to BBC News, the president and chairman of the ports of Calais and Boulogne, Jean-Marc Puissesseau, said: "Even if the sea is not looking so rough, in the middle [of the English Channel] there are always many waves. It is dangerous."