Hollande takes campaign to London

"I don't see any reason why Hollande, if elected, would create problems for Franco-British defence collaboration," says Charles Grant, director of the CER. "On defence, Germany is not as reliable a partner for France as the British are. The fact that Hollande has said that France will say a full member of NATO also means there should be no undermining of the bilateral relationship."

However, Mr Grant believes that Hollande remains largely unknown to the British political establishment and will be as difficult a partner for Mr Cameron on European Union issues as Nicolas Sarkozy has been.