At least 7,000 migrants and refugees mainly from Afghanistan, Iraq and Syria are trapped in Serbia, many spending months in a country culturally and financially ill-equipped to care for them and where few of them want to stay.

Refugee camps are packed and only women and children are likely to be let into them, leaving the men to seek shelter where they can — in abandoned warehouses in central Belgrade, or the fields just south of the border.

Although that route was closed off last March, Serbian authorities estimate a further 110,000 migrants have passed through the country, many using smugglers to cross Serbia and its barbed-wire border with Hungary.