French President Emmanuel Macron and UK Prime Minister Boris Johnson agreed during a phone call to step up action against "lethal" sea crossings by migrants.

This comes after at least 27 migrants trying to reach Britain from France through the Channel died on Wednesday when their boat sank off the northern French coast.

A British government spokesperson said Johnson and Macron agreed that the "tragic loss of life was a stark reminder that it is vital to keep all options on the table to stop these lethal crossings and break the business model of the criminal gangs behind them."

The disaster caused the highest death toll since at least 2018 when migrants began using boats to cross the Channel. It comes as tensions grow between London and Paris over the record numbers of people crossing. 

French Interior Minister Gerald Darmanin said four suspected traffickers accused of being directly linked to the lethal crossing in a long inflatable boat had been arrested. A fifth suspect was arrested early today.

Darmanin told reporters in Calais that only two survivors had been found but they are in a very critical condition. He said five women and one little girl were among the dead, and Calais mayor Natacha Bouchart said a pregnant woman was also one of the victims.

An increasing number of migrants

According to the French authorities, 31,500 people attempted to leave for the UK since the start of the year and 7,800 people have been rescued at sea, figures which doubled since August.

In the UK, Johnson's Conservative government is coming under intense pressure, including from its own supporters, to reduce the numbers.

British authorities pointed out that more than 25,000 people have now arrived illegally this year, already triple the figure recorded in 2020.