French police are holding 10 people suspected of involvement in the November 2021 Channel drowning of migrants in which 27 people died, a judicial source said Thursday.

One has been charged with manslaughter and people-trafficking, and the nine others were to be taken before a judge who will decide whether to charge them as well, the source said, asking not to be named.

Police had arrested 15 suspects in an overnight operation Sunday to Monday as part of their months-long investigation into the disaster, releasing five of them without charges.

The death of the 27 in late November was the worst accident in the Channel since 2018, when the narrow strait became a key route for migrants from Africa, the Middle East and Asia who have been increasingly using small boats to reach England from France.

Among the 27 -- aged seven to 47 -- were 16 Iraqi Kurds, four Afghans, three Ethiopians, one Somali, one Egyptian and one Vietnamese migrant.

There has been much cross-Channel tension over migrants policy
There has been much cross-Channel tension over migrants policy AFP / FRANCOIS LO PRESTI

Only two people survived the disaster, which sparked tension between the British and French governments.

President Emmanuel Macron vowed France would not allow the Channel to become a "cemetery".

France urged Britain to help more with cracking down on people-smuggling gangs, with Interior Minister Gerald Darmanin saying: "We need intelligence. Responses to requests from the French police are not always given."

The rebuke followed British Prime Minister Boris Johnson's proposal to send back all migrants and asylum seekers who land in England to France, a move rejected by Paris.

The number of migrants seeking to cross the Channel from France to England surged in the first half of this year
The number of migrants seeking to cross the Channel from France to England surged in the first half of this year AFP / Sameer Al-DOUMY

Following Britain's departure from the European Union, it does not have a returns treaty with France or the wider EU.

The spat added to a litany of post-Brexit rows between the two sides, which also include a dispute on fishing rights in the Channel which at times threatened to spill over into a full-blown trade war.

Despite a more conciliatory tone since, and promises of more cooperation, the number of migrants seeking to cross the Channel from France to England surged in the first half of this year, according to the French interior ministry.

From January 1 to June 13, there were 777 attempted crossings involving 20,132 people, up 68 percent on the same period last year, it said.

The ministry said French security forces had prevented most of the crossings, with 61.39 percent of the attempts thwarted in the first half, up 4.2 percent on last year.

The figures for all of 2021 had already been a record but the latest statistics show this could be beaten if current trends continue, as summer weather settles in that encourages more crossings.

Some 52,000 people tried to cross in 2021, with 28,000 of the migrants succeeding, according to the French authorities.

The numbers come as the UK seeks to toughen its policy against arrivals.

Britain has repeatedly accused the French authorities of not doing enough to stop the crossings.

In a controversial policy, the UK is planning to deport illegal migrants, including those who arrive across the Channel, to Rwanda under an agreement with the African nation.

However, the first flight earlier this month was cancelled after a last-minute intervention by the Strasbourg-based European Court of Human Rights (ECHR) which enraged London.