Aid agencies have warned that the problem of migrants camping out in Calais before trying to reach Britain has risen to a level of crisis not seen before.Their numbers in the French port have swollen from around 1,000 in April to 3,000 this month, and it is predicted that up to 4,000 more will arrive in the coming weeks. Aid workers warn that some of the sprawling makeshift campsites, known locally as the Jungle, have become so large as to be untenable. Dozens of migrants have occupied derelict barns and erected tarpaulin-covered wood structures big enough for families, as many wait to try their luck at hiding on lorries to Dover. Maya Konforti, a volunteer for l’Auberge des Migrants, an aid group based in Calais, said the number of migrants arriving was ‘definitely climbing’. She said, ‘The situation is catastrophic. They don’t have enough tents, blankets or food and with Ramadan it’s more difficult.’ She urged Britain to ease the burden on France.