Immigration debate masks benefits to EU's top economies

A man carrying a bag adorned with a British Union Jack flag steps into a bus departing from Sofia's central bus station to London via Austria, Germany and France January 2, 2014. REUTERS/Stoyan Nenov

LONDON/BERLIN/PARIS (Reuters) - An unemployed builder sits on the pavement, begging for small change next to a slogan saying "EU policy at work - British workers are hit hard by unlimited cheap labour".

The arresting image comes from an election poster for the United Kingdom Independence Party, a once-fringe movement that wants to withdraw Britain from the EU and looks set to garner the most votes in next week's European Parliament polls.