While the eyes of the media were on Barclays, David Cameron casually suggested that the UK would block Greek people  from entering Britain if their country left the euro. He told the Commons liaison committee:
[A]s I understand it, the legal powers are available if there are particular stresses and strains. You have to plan, you have to have contingencies, you have to be ready for anything – there is so much uncertainty in our world. But I hope those things don't become necessary.
Leaving aside Cameron's cynical populism, what "legal powers" is he referring to? The free movement of people, along with the free movement of goods, capital and services, is one of the four fundamental freedoms of the European Union. While member states have legally limited immigration from new EU countries (as we currently do in the case of Bulgaria and Romania), no country has ever restricted migration from established members. Even "in the event of war", EU law states, "Member States shall consult each other with a view to taking together the steps needed to prevent the functioning of the internal market being affected".
There is little prospect of the EU allowing Britain to unilaterally suspend migration from Greece, a member state of 31 years' standing. It was as recently as April that the EU Commission warned the UK  to fully comply with European law on the free movement of people or face an EU court case. In addition, as the excellent Free Movement  blog notes, since Article 18 prohibits discrimination  based on nationality, any restrictions on Greek immigration would need to apply to all EU citizens.Would Cameron really be willing to see free movement suspended for UK citizens? (An event that would have deleterious consequences for his net migration target.)
Worse than the Prime Minister's feeble understanding of EU law, however, was his sinister suggestion that Greek people represent a threat to our economy. He told MPs: "I would be prepared to do whatever it takes to keep our country safe, to keep our banking system strong, to keep our economy robust. At the end of the day, as prime minister, that is your first and foremost duty." So, the biggest threat to our "robust" (recession-plagued) economy and our "strong" (crooked) banking system is posed by our fellow Europeans. Until yesterday, no country, including those that share a border with Greece, had suggested pulling up the drawbridge and abandoning the principle of free movement. How shameful that it is the UK that is the first to do so.