The Home Office is planning for a possible large increase in immigration from Greece and other European Union nations in response to the crisis in the euro, Theresa May has revealed.
The Home Secretary told The Daily Telegraph "work is ongoing" to deal with large movements of people in the event of the break-up of the single currency.
Should Greece leave the euro and go bankrupt, millions of people could lose their jobs and may look for work abroad. There are fears too of the contagion spreading to other weak eurozone countries.
Britain, as a non-eurozone country, may be seen as an attractive alternative.
Mrs May did not indicate the sort of response that was under consideration.
In normal circumstances the Government's hands are tied because EU nationals are largely entitled to live and work anywhere in the single market.
But she said the Government was "looking at the trends" on immigration from struggling European economies. She said there was no evidence of increased migration at present, adding that it was "difficult to say how it is going to develop in coming weeks".
Asked whether emergency immigration controls are under consideration, Mrs May said: "It is right that we do some contingency planning on this (and) that is work that is ongoing."
Prime Minister David Cameron cast doubt on the future of the euro last week when he warned the eurozone that it "either has to make up or it is looking at a potential break-up".
"That's the choice they have to make and it is a choice they can't long put off," he told the Commons.