Steve Bannon - the man who helped Donald Trump ride a populist wave to power in the US - has backed the struggling French far-Right leader Marine Le Pen at a key conference aimed at giving her Front National party a new name and a new direction.

“History is on our side and it will take us from victory to victory,” he told thousands of FN supporters gathered in Lille in the hope of reviving a party battered by electoral failures, defections, and vicious infighting.

“You are part of a worldwide movement that is bigger than Italy, bigger than Poland, bigger than Hungary,” Mr Bannon said, referring to the electoral successes of far-Right and nationalist parties in those countries.

The former White House adviser and ex-head of Breitbart News, who has repeatedly expressed support for Europe's far-Right movements, was a surprise guest at the FN conference, with his speech only being announced late on Friday.

"The king of fake news and of white supremacists at an FN summit... why am I not surprised? Change of name (for the Front National) but not of the political line," said the head of President Emmanuel Macron's centrist En Marche party, Christophe Castaner.