Senior German politicians and police officials said unresolved security problems could mean increased crime and illegal immigration following Friday’s enlargement of the European Union’s Schengen border-free zone.

Josef Scheuring, head of the GdP German police trade union, said on Thursday: “Germany is not well prepared for this [enlargement] process” in which people in Poland, the Czech Republic, six other eastern European countries and Malta today gain passport-free travel to most of the EU.