The 22-year-old Eritrean suffered a head injury and internal bleeding as Channel Tunnel briefly closed by migrants on railway.
Migrants in Calais chanted 'We are not animals' as French, UK ministers announced new measures including a joint 'control and command centre'.
French interior minister Bernard Cazeneuve and his UK counterpart will meet in Calais on Thursday over new deal to contain migrant crisis.
The survey followed PM Cameron's talk of a 'swarm' of migrants while his FM warned of 'marauding' migrants threatening living standards.
Senior UN officials says situation is a 'civil emergency' but adds that with right action it is a 'manageable situation'.
Instead of pledging higher fences and more sniffer dogs politicians should fix broken asylum system, argues charity boss.
In return for help in making the Channel Tunnel and the port at Calais more “secure”, France has agreed to monitor Britain's borders on its behalf. On the Italian frontier, meanwhile, French police are searching for migrants who have crossed the Mediterranean. As Carine Fouteau reports, interior minister Bernard Cazeneuve has taken on the mantle of Europe's new gatekeeper, at the risk of breaching European law.
In joint article for British newspaper, UK home secretary and French counterpart say the situation is part of a 'global migration crisis'.
But police say that number of migrants trying to enter Britain through Channel Tunnel eased slightly after deployment of extra 120 officers.
Interior minister Bernard Cazeneuve said extra 120 officers would be temporarily based in Calais and would help to secure the terminal area.
Victim, said to be Sudanese and aged between 25 and 30, is reported to have been hit by a lorry as UK's PM calls Calais situation 'very concerning'.
The mystery of the remains found in wetsuits was solved by a dogged Norwegian journalist and highlight the desperate plight of Calais migrants.
Tunnel operator said two migrants were found injured on a train and another on tracks after 'a large number' passed through French entrance.
A police source said the UK-bound man fell off a freight carriage he mounted in France, the second migrant death in the tunnel in a month.
Eurotunnel said services were delayed and cancelled after the migrants attempted to access restricted areas on the French side.