More than 9,500 migrants crossed or attempted to cross the English Channel from France to Britain last year, a fourfold increase from 2019, French maritime officials said Friday.

Migrants entering Europe have long sought to reach Britain in the belief it is their best chance of securing asylum or residency, prompting growing numbers to make the journey across the perilous waters of the busy shipping lane.

"In 2020, 868 incidents involving attempts or crossings of migrants by boat were recorded in the Channel, involving 9,551 migrants," the maritime authority in charge of the Channel and the North Sea said.

Six people died and three went missing, up from four deaths in 2019, when just 203 crossings or attempts were detected -- itself a fourfold increase from the number in 2018.

France and Britain signed a new accord in November aimed at shutting down the route via increased patrols and the use of radar and drones to spot boats quicker.

The figures for the Channel came as the EU's border agency said Friday that attempted crossings into the European Union were at their lowest level since 2013, largely due to travel restrictions linked to the Covid-19 pandemic.

A total of 124,000 illegal crossing were registered last year, down 13 percent, with the biggest declines along the Eastern Mediterranean migratory route through Greece, Warsaw-based Frontex said in a statement.

In France, aid groups say around 1,000 migrants are currently massed in squalid camps near the northern French port of Calais, where police regularly move in and tear down tents.

For Francois Guennoc, president of the Auberge des Migrants association, the surge in Channel attempts reflects a variety of factors, not least "an increase in success rates."

People smugglers have refined their strategies, he said, such as launching several boats at a time in the hope at least some will evade detection.

The introduction of new surveillance tools to detect people hiding among the thousands of trucks heading to Britain through the Eurotunnel has also boosted numbers on the sea route, Guennoc said.

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