In February, an ECJ advocate general said this was in line with the aims of the EU single market - a border-free zone for goods and services.

BBC: Premier League games can be shown on foreign decoders

Over the past year the Danish, French and Italian governments have rolled back the Schengen passport-free zone and reintroduced limited border controls.

ECONOMIST: Immigration

Mr Tusk just about accuses his fellow EU leaders of hypocrisy for talking of integration and yet undoing the Schengen passport-free zone by reimposing some border controls.

ECONOMIST: Charlemagne

They have allowed some of the country's biggest industrial firms to foster more pliant company unions, such as Ford's, and many maquiladora (free zone) factories along Mexico's northern border get away with unions that are registered (thus excluding any others) but otherwise non-existent.

ECONOMIST: Mexico��s trade unions stick to the same old tune

The BBC's James Reynolds briefly crossed over the Turkish side of the border into Iran, where he was invited into a free trade zone.

BBC: Iran currency plunge bites into border trade with Turkey