Under a deal signed by Home Minister Theresa May and her French counterpart Bernard Cazeneuve, British teams will help bust smuggling gangs and reduce nightly attempts by desperate migrants and refugees to break into the Channel Tunnel.
But in an interview with AFP, the head of the Red Cross slammed the "indifference" of governments across Europe that has allowed a continental crisis to take hold.
"What will be the saturation point? When will everybody wake up to see that it is a real crisis?" Elhadj As Sy, head of the International Federation of Red Cross and Red Crescent Societies, said in Geneva.
The new deal for Calais includes extra French policing units, additional freight searches, and tighter security at the entrance to the Channel Tunnel near Calais through more fencing, cameras, floodlighting and infrared detection technology.
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A control centre will also be built there to try and bring down entry attempts, which at the start of the summer numbered up to 2,000 per night, but have since reduced due to tighter security.
Some 3,000 people from Africa, the Middle East and Asia are camped in Calais, and at least nine have died trying to cross over into Britain, where many have family and work is thought easier to find.
These numbers are a tiny fraction of those entering other European countries, particularly Germany, which said this week it expects a new record 800,000 asylum seekers in 2015 -- far more than the 500,000 initially expected.
EU border agency Frontex on Tuesday reported a record high of 107,500 migrants at the European Union's borders last month.
And the number of migrants arriving in debt-crippled Greece is accelerating dramatically, with nearly 21,000 landing on the overstretched Greek islands last week alone, the United Nations said.
Red Cross chief Sy said the only way to stop the traffickers was to increase legal means of migration.