It is time that Europe's politicians admitted to voters that governments cannot stop people moving across borders. Despite efforts to build a Fortress Europe, more than a million foreigners bypass its defences each year: some enter covertly; most overstay their visas and work illicitly. While draconian policies do curb migration somewhat, they mostly drive it underground.

That creates huge costs: a humanitarian crisis, with thousands drowning each year trying to reach Europe and thousands more detained; the soaring expense of border controls and bureaucracy; a criminalised people-smuggling industry; an expanding shadow economy, where illegal migrants are vulnerable to exploitation, labour laws are broken and taxes go unpaid; mistrust of politicians who cannot fulfil promises to halt immigration; corroded perceptions of immigrants as law-breakers rather than enterprising people; and the mistreatment of refugees to deter people who want to work from applying for asylum, besmirching our commitment to help those fleeing terror.