François Fillon urges supporters 'not to give up fight' as his wife hits back at opponents over 'fake jobs' scandal

French presidential candidate François Fillon urged his supporters “not to give up the fight” in the race to the Élysée Palace after his wife hit back at critics in a “fake work” scandal that has all but ended his campaign.

Speaking in front of a crowd of thousands in Paris, the 63-year-old candidate for Les Républicains party embarked on a last-ditch attempt to save his candidacy, giving what commentators dubbed “the speech of his life”.

In calling the rally, Mr Fillon aimed to show his opponents he still has a large body of dedicated support in spite of being mired in a weeks-long series of corruption allegations.

Later in the day, he declared during a television interview that he would not withdraw his candidacy, despite growing pressures for him to go.

"Nobody can prevent me from being a candidate," he said, adding that his decision was based on the general interest and that any "improvised candidate" would lead to failure.

Meanwhile, his Wales-born wife Penelope Fillon defended having worked for her husband in her first interview since those claims emerged. Newspaper allegations, that she and the couple’s children were paid substantial sums for parliamentary aide work they never carried out, have seen Mr Fillon go from clear favourite to third in the polls behind youthful independent Emmanuel Macron and far-right leader Marine Le Pen.

Mr Fillon and his wife have repeatedly denied any wrongdoing and the right-wing candidate slammed the “Penelopegate” scandal as a “political assassination”.

Speaking to the Journal du Dimanche, Ms Fillon said: “He needed someone that carried out his tasks. If it hadn’t been me, he would have paid someone else to do it, so we decided that it would be me."

She said the breaking scandal had felt like being “struck by lightning”.

“This is the worst I have had to live through in my life," she said. "I was so surprised by the violence and hysteria that I have found refuge in my Welsh stubbornness.

“I did not believe that I was doing politics. I was working for my husband. My role was to help him interact with his constituency as an elected representative."

On the prospect of her husband stepping down from the presidential race, she said: "I told him that he had to keep going until the end. But the decision will be down to him."

Ms Fillon's words of support for her husband come as senior conservative politicians said they would propose an alternative candidate to Mr Fillon as soon as Monday morning.

Christian Estrosi, a senior Conservative politician and a close ally of former President Nicolas Sarkozy, told BFM TV: “In the coming hours, we will propose an initiative.

"We do not have the time to debate who has the most talent. I don't think any of the forty-somethings in our political movement, who have talent, can take on the role to bring us together."

"The easiest thing obviously ... Is the person who came second in the primaries and that quite simply is Alain Juppé,” he said.

Mr Estrosi is not the only one to call for Mr Fillon to leave.

The head of France’s centre-right Union of Democrats and Independents (UDI) party, Jean-Christophe Lagarde, also said he wanted Mr Fillon to quit the election race in favour of former prime minister Mr Juppé. He warned that if Mr Fillon did not stand down, it would mean defeat for the conservatives.

Speaking on Europe 1 radio, he said: “With Fillon it's a certain failure. This [rally] is an excess because you don't put the street up against the [state’s] institutions. Even if there are 200,000 people, to win a presidential election you need 20 million people.

“In the Olympics when the gold medal winner is disqualified, then it’s the silver medal holder that takes over.”

Paris mayor Anne Hidalgo also spoke out against the rally saying it was “against republican values” and she previously urged Mr Fillon “to get his dignity back” by calling it off.

Even inside the Fillon camp, support seemed to dwindle.

A poll published in the Journal du Dimanche showed more than 70 per cent of French voters want Mr Fillon to withdraw his presidential bid.

The same survey suggests Mr Juppé, who lost to Mr Fillon in the November party primary, was best placed to step in. He received a personal approval rating of 64 per cent compared to 29 per cent for Mr Fillon.

Immediately following Mr Fillon’s television interview, Mr Juppé announced that he will hold a press conference on Monday morning.

It comes after Mr Fillon's campaign manager Patrick Stefanini announced his resignation – the third aide to quit in quick succession.

Mr Fillon, who is renowned for his reactionary views, also pulled out of an early Monday morning radio appearance that aimed to discuss his campaign.

Europe 1 radio presenter Thomas Sotto tweeted: “François Fillon has officially cancelled his appearance on Europe 1’s morning show tomorrow.”

Opinion polls continue to show Mr Fillon would fail to make it to the second round of the election. Instead, centrist candidate Macron is benefiting from a boost in the polls and is consolidating his position to win the election in a head-to-head against Front National candidate Marine Le Pen.

The first round of the French elections will be held on 23 April and all presidential candidates must be formally endorsed by at least 500 elected officials before 17 March.