France’s Interior Minister must resign in the wake of the Nice attack, Front National leader Marine Le Pen has said.

Speaking this weekend, Ms Le Pen called on Bernard Cazeneuve to quit after the 12th Islamist attack to hit the country in the space of 18 months.

“In any other country in the world, a minister with a death toll as horrendous as Bernard Cazeneuve – 250 dead in 18 months – would have resigned a long time ago,” she said.

Ms Le Pen added that the main cause of the wave of Islamist attacks in France is Islamic State and their “murderous ideology that we let develop in our country”.

That ideology is not developing by itself, however, but is being helped by the weakness and inaction of the French political establishment in dealing with the threat.

“This is the result of a state failing in its first priority, which is the protection of our citizens,” she said.

Her comments came just a day after she called for French authorities to “declare war” on Islamic extremism.

“The 14th of July — the day we celebrate our homeland, its freedom, a holiday — has been turned for the French into a day of terror, of harrowing suffering,” she said.

“We must not see terror attacks come after another and count more deaths without taking action.

“The war against the scourge of Islamist fundamentalism has not begun; it’s now urgent to declare it. We will truly engage in it by implementing a set of measures I have already detailed and which I’ll have the occasion to come back to, which will aim at tackling the roots of the phenomenon.”

Ms Le Pen and her party have been surging in polls in recent months as both of France’s establishment parties fail to get to grips with immigration and the growing Islamist threat.

A survey for Le Monde last month put Ms Le Pen on 28 per cent for next year’s presidential election, ahead of Nicolas Sarkozy on 21 per cent and incumbent François Hollande on just 14.

Even if Ms Le Pen did top the first round, however, the French system means that the top two candidates go forward to a run-off, allowing her opponents to back the other candidate and prevent her winning the presidency.