OPINION: Europe's open borders are precious, fragile and under threat
As countries within the EU reintroduce checks on their Schengen zone borders, John Lichfield looks at why this threat to the 'invisible achievement' of open borders matters to the whole of Europe.
Tomas Kauer - Moderator 
As countries within the EU reintroduce checks on their Schengen zone borders, John Lichfield looks at why this threat to the 'invisible achievement' of open borders matters to the whole of Europe.
