No European Union country has gained more than the United Kingdom from immigration by EU citizens, said EU home affairs commissioner Cecilia Malmström, speaking at Chatham House.
'Firstly, they have to finance their presence there and their budget is under strain. Secondly, despite what you see on the news, Crimea is not full of people waving Russian flags and cheering it on, so they'll have a security problem in a general way. Thirdly, because all Crimea's links are with Ukraine,' says Sir Andrew Wood.
Rich nations could try to block Russian president Vladimir Putin's wealthy supporters from accessing the world's financial markets. 'That would hurt us more than it hurts them,' says Keir Giles.