Italy publicly backs David Cameron's vision for two-speed Europe in new boost for PM

“This initiative is significant,” said Charles Grant, the director of the Centre for European Reform, a pro-EU think-tank, “in that it recognises the reality that the European Economic Union is a multi-currency union, in which the various countries can choose their own, differing paths of integration.”

However, in a sign of the battles that lie ahead in the coming months, Mr Grant warned that the UK still faced stiff opposition from the more federalist-minded countries and the European Commission, whose president, Jean-Claude Juncker, is a constant champion for ‘more Europe’.

“Some EU countries are wedded to the old thinking – that all must embrace the euro and ever closer union – and they won’t welcome this initiative,” Mr Grant added.