The attacks have sounded the alarm bell in Germany over the consequences of mass migration. A country dogged by guilt over its Nazi past, it has enjoyed its recent role as saviour of Europe, welcoming in foreigners from the war-divided Middle East and Africa’s poverty hotspots.

When the migrants began arriving in their thousands each day last summer, there were welcoming parties across the country. ‘We love refugees!’ proclaimed banners outside reception centres.

Yet that warm hospitality is now being replaced by fear, as a society renowned for its good order begins to buckle under the strain — and to worry if it has made a mistake.

Figures this week revealed that 1.1 million newcomers registered for asylum in Germany in 2015. Many more — including potential jihadists and opportunists pretending to be refugees — are suspected of slipping in under the radar since August, when German Chancellor Angela Merkel controversially announced she would welcome all Syrian migrants who knocked on the door. Mrs Merkel has since dramatically changed her tune, saying this week that she wanted to stem the flow of migrants into the European Union, while keeping all borders open.

Yet the influx into Europe since she made her grand gesture shows no sign of abating. German ministers say 3,200 migrants a day continue to enter the country.