“The English cannot enter. You have to show identity papers and only the French can go in. If you want to know why, call the president. The order comes from up there.”

British aid workers have been prevented from distributing food and clothes to migrants in the north of France by police officers claiming to be acting on the orders of President Macron.

The officers allowed French aid workers into a makeshift camp in Grande-Synthe, near Dunkirk, which is home to at least 500 mainly Iraqi Kurdish migrants, but refused permission for British volunteers from the same charity to follow.

The Refugee Women’s Centre, a French charity that aims to help woman and child migrants sleeping rough in woods in Grande-Synthe, said that Britons had arrived with a pushchair and blankets for a migrant family with a disabled 11-year-old daughter only to be told by police: “You’ll need to get a French volunteer to do that.”

Associations said that the ban on Britons was part of a deliberate drive to disrupt aid programmes for migrants seeking to cross the Channel from northern France in the hope that they will give up and go elsewhere.

Officials accuse charities of encouraging migrants to remain in Calais and Dunkirk instead of moving to shelters in other French towns. In private, some are particularly scathing of the dozens of British volunteers present in the area, whom they accuse of undermining attempts to resolve the crisis along the English Channel coast.