France has turned even more viscerally eurosceptic than Britain over recent months, profoundly altering the political geography of Europe and making it impossible to judge how Paris might respond to Brexit.

An intractable economic crisis has been eating away at the legitimacy of the French governing elites for much of this decade. This has now combined with a collapse in the credibility of the government, and mounting anger over immigration.

A pan-European survey by the Pew Research Center released today found that 61pc of French voters have an “unfavourable” view, compared to 48pc in the UK.

A clear majority is opposed to “ever closer union” and wants powers returned to the French parliament, a finding that sits badly with the insistence by President Francois Hollande that “more Europe” is the answer to the EU’s woes.

“It is a protest against the elites,” said Professor Brigitte Granville, a French economist at Queen Mary University of London. “There are 5000 people in charge of everything in France. They are all linked by school and marriage, and they are tight.”

Prof Granville said the mechanisms of monetary union have upset the Franco-German strategic marriage, wounding the French psyche. “The EU was sold to the French people as a `partnership’ of equals with Germany. But it has been very clear since 2010 that this is not the case. Everybody could see that Germany decided everything in Greece,” she said.