Such disasters seem inevitable given the recent upsurge in illegal migration by perilous sea crossings.

ECONOMIST: Illegal immigration to Italy

Yet, given today's fears in western Europe over legal and illegal migration, the expansion of Schengen is some way off.

ECONOMIST: Central Europe

The issue of illegal migration, and the treatment of Mexicans on the border, is a source of abiding tension between the US and Mexico.

BBC: Felipe Calderon in December 2010

The UNHCR says tighter border controls at sea, with Mediterranean countries co-ordinating their efforts, have simply shifted the problem of illegal migration to the Greek land border.

BBC: Germany sounds alarm on migrants in Greece

This produces confusion at the European level, making it harder to manage legal migration (and properly managed legal migration may be the best single cure for illegal migration).

ECONOMIST: Charlemagne

"We intend to use the renewal of talks to reaffirm both sides' commitment to safe, legal and orderly migration, to review recent trends in illegal Cuban migration to the United States, and to improve operational relations with Cuba on migration issues, " State Department spokeswoman Heide Bronke-Fulton told CNN.

CNN: U.S. offers to renew talks with Cuba on immigration

According to the Mexican Migration Monitor run by Roberto Suro of the Annenberg School, illegal Mexican migration exceeded 368, 000 in every year from 2003-2009, with a high of 682, 000 in 2007.

WSJ: Review & Outlook: Immigration Reform Roadblock

If we take the steps set out today, and deal with all the different avenues of migration, legal and illegal, then levels of immigration can return to where they were in the 1980s and 90s, a time when immigration was not a front rank political issue.

BBC: In full: David Cameron immigration speech

Granted, there is social expense, disruption and even danger from unchecked in-migration, especially if it is illegal.

FORBES: Magazine Article