Marine Le Pen was today poised for a historic breakthrough in France’s nail-biting presidential race.

The far-Right leader is confident her chances of winning the election’s first round have been strengthened by last week’s terrorist murder of a police officer on the Champs-Élysées.

But with the country on high alert as voters head to the polls, 48-year-old Le Pen – dubbed ‘Madame Frexit’ for threatening to follow Britain out of the EU – was accused of using the shooting for her own ends.

Marine Le Pen was today poised for a historic breakthrough in France’s nail-biting presidential race

Her campaign has been dominated by anti-Islam and anti-immigration rhetoric and critics said she has used the violence to stoke further hostility.

She is locked in a duel with centrist front-runner Emmanuel Macron, 39, a staunch defender of the single market who has told Theresa May he favours a ‘hard Brexit’.

If, as expected, Le Pen and Macron are successful in the first round of voting today, they will face each other in the run-off on May 7.

But analysts say the battle for the Élysée Palace is by no means a two-horse race.

Le Pen has moved from 22 per cent to 23 per cent in the latest opinion poll while her three rivals have all lost half a percentage point of support.

Macron dropped back to 24.5 per cent, while republican candidate François Fillon and leftist candidate Jean-Luc Mélenchon were back on 19 per cent.

The far-Right leader is confident her chances of winning the election’s first round have been strengthened by last week’s terrorist murder of a police officer on the Champs-Élysées

Experts said a Le Pen victory in the first round could mean cheaper holidays for Brits heading to Europe.

Kathleen Brooks, of City Index Direct, said: ‘I think if Le Pen wins today by a wide enough margin, then the euro will fall significantly, possibly to the lowest levels we’ve seen this year. And a weak euro will initially be great for us as everything will be much cheaper in Europe.’

Le Pen’s father, the convicted racist Jean-Marie Le Pen, caused shockwaves around the world in 2002 when he came second in the first round. He then went on to lose to Jacques Chirac by a landslide of more than 80 per cent.

But Marine Le Pen is convinced she can go one better by positioning herself as the candidate who is toughest on terror.

She had pledged to ‘immediately reinstate border checks’, to expel foreigners and to ban all immigration, whether illegal or not. Supporters include Donald Trump who said the Paris attack would ‘have a big effect on the presidential election’ because the French people ‘will not take much more of this’.

But French Prime Minister Bernard Cazeneuve accused Le Pen of ‘shamelessly seeking to exploit fear and emotion for exclusively political ends’. Mr Cazeneuve pointed out that Karim Cheurfi, the 39-year-old responsible for the murder of traffic officer Xavier Jugelé, 37, was a born and bred Frenchman.

Le Pen has called for negotiation with Brussels on a new EU, followed by a referendum; extremist mosques closed and priority to French nationals in social housing; and retirement age fixed at 60.

Macron forged a reputation with his ‘Macron Law’, a controversial reform bill that allowed shops to open more often on Sundays. On security, he has said France is paying for the intelligence jobs cuts made when Fillon was PM between 2007 and 2012.