On a rainy November morning, dockers from Calais are firing flares in protest against port job losses outside the regional council in Lille, the capital of France’s old industrial north. Inside the plush chamber, a tall, solidly built blonde woman in jeans and boots crooks a leg over her knee and flicks through a news magazine. Marine Le Pen, leader of the Front National, which has 18 council seats, has dropped in from a day at the European Parliament in nearby Brussels, where the party has 23 MEPs. Le Pen looks bored as the councillors drone on about allocating €1.1bn of EU money to help revive the bleak economy of Nord-Pas-de-Calais.

When her moment comes, she launches into a riff on the evils of the Union. EU funds just reinforce the dictatorship of Brussels and impoverish the downtrodden rural and small-town folk of the region, she says. “I have to remind people ad nauseam that this is not European money. It’s part of French taxpayers’ money that transits through Brussels with the rest going to pay for central and eastern Europe.” With that, the terror of the French political establishment picks up her papers, closes her beige wool jacket and slips out to a car for the drive back to Paris, missing the council’s splendid lunch. So it goes for Le Pen as she tills the fertile electoral soil of the north as the prelude to a run at the Élysée Palace in two years’ time.

France has been frightening itself with visions of a President Le Pen since 2002 when Jean-Marie, Marine’s father and the founder of the far-right Front, landed in the run-off for the presidency. He was roundly defeated by Jacques Chirac when voters rallied in a “republican front” to block the leader of a pariah party. Now, with his pugnacious daughter in charge of the family firm, the prospects of an anti-Front reflex are dimmer and Marine’s prospects look bright.

The country is in a foul mood. The sense of dispossession at the hands of a hostile world is feeding contempt for la France d’en haut – the governing caste. President François Hollande and his Parti Socialiste (PS) have been disowned by many of their disappointed voters, discredited by scandal and economic failure. Civil war is tearing apart the Union pour un Mouvement Populaire (UMP), the centre-right opposition whose leadership is about to be reclaimed by Nicolas Sarkozy, the former president.

Marine Le Pen, 46, the youngest of the 86-year-old patriarch’s three daughters, is gliding above this desolate landscape, a protective, Joan of Arc-like warrior in the eyes of her followers. The blunt-spoken Le Pen fille remains divisive. More than six out of ten people do not trust her to run the country, according to an October poll. But she ranks as one of France’s most popular politicians, with a 46 per cent approval rating, after managing to shed much of the racist stigma that made her father unelectable since she became the party’s leader in 2011. After four decades as an uncivilised stain on the electoral landscape the revamped Front is on the brink of the mainstream. As Manuel Valls, the French prime minister, put it in a wake-up call to his bedraggled PS in September: “The Front National is at the gates of power.”

In the spring, the “de-demonised” Front won the biggest score of any party in the European elections and took control of a dozen electoral areas, including the towns of Béziers and Fréjus and the seventh arrondissement of Marseilles. It also won in Hénin-Beaumont, a run-down rust-belt town 20 miles south of Lille, which has become the shop window for Front administration and the base for Le Pen’s battle for the north.

Her plan goes like this. Under an Hollande reform, Nord-Pas-de-Calais, one of the 22 regions of metropolitan France, is to be merged next year with Picardy, creating a super-region of six million people under a planned shrinkage to 13 new administrations. The Front has long been popular in the north, which is at the top of its arc of strongholds extending south-east through Alsace-Lorraine to the Mediterranean coast. Le Pen won 23 per cent of the northern presidential vote in 2012 and came just behind Sarkozy. With its new creed of defending the dispossessed, the Front may manage to take Nord-Picardy in elections late next year and that would put Le Pen within credible reach of the Élysée in 2017.

This scenario is not wishful thinking. It was put to me by Le Pen’s chief local adversary. Daniel Percheron, the Socialist who has presided over the north for 14 years, thinks that Le Pen can win the super-region despite her part-time presence. “From that moment, we will be facing a presidential election of a new kind. She will have a new credibility, a legitimacy that has never existed for the far right in France,” Percheron said. A typical provincial baron, the 72-year-old senator sighed as he acknowledged Le Pen’s skill at winning over his own clientele. Old taboos against the far right have fallen, he said. “Left-wing voters are crossing the red line because they think that salvation from their plight is embodied by Madame Le Pen. They say ‘no’ to a world that seems hard, globalised, implacable. These are working-class people, pensioners, office workers who say, ‘We don’t want this capitalism and competition in a world where Europe is losing its leadership.’ ”

Le Pen, whom I have interviewed several times, going back to 2003, is amused by the left’s indignation over the way that she has broadened her attraction, softening the anti-immigration rhetoric and adding Socialist voters to the party’s hard-right faithful. When we last talked at length, in November 2013 in Le Carré, the party’s seat in Nanterre, a western suburb of Paris, she mentioned that Charles de Gaulle – whom she admires – was accused of being both a fascist and a Bolshevik.

In her husky smoker’s voice (she quit tobacco two years ago and now vapotes with electronic cigarettes) she said: “France is neither on the right nor the left – it’s just France . . . I don’t have the feeling that I tell patriots on the left different things from what I say to patriots of the right.”

Physically imposing, caustic and never letting her guard drop, Le Pen is an uncanny chip off the old granite block as she expounds her harsh, France-first creed. The armour was already in place when I first visited her 11 years ago. Back then, she was the party’s young legal counsel and was being groomed by her father for leadership.

She became hardened early because, as a Le Pen, she was always an outsider, she told me. She was the “daughter of the monster”, as she put it, growing up in the comfort of Montretout, the mansion at Saint-Cloud bequeathed to her Breton-born father by a party supporter in the late 1970s. When she was eight, a bomb had destroyed the family flat and she had felt no sympathy from anyone. No one was arrested for the crime.

There were years of Jean-Marie’s constant absences, and humiliation as a teenager when Pierrette, her mother, posed naked for Playboy. That was an act of revenge in a feud with her husband after she walked out on him, abandoning her daughters to set up home with a journalist. During Marine’s twenties, there came the paternal banishment of Marie-Caroline, the eldest of the three Le Pen daughters, after her husband defected to Bruno Mégret, a Front lieutenant who mounted an abortive takeover of the movement.

The wayward Marie-Caroline has never been accepted back into the fold but Pierrette was given a home on the Montretout estate, in the same complex as Marine, and until recently she helped take care of Marine’s three teenage children. Jean-Marie lives nearby with Jeanne-Marie (“Jany”), his second wife.

Le Pen scoffs at talk of a dynasty but she is the heiress to the family enterprise that sprang from the murky pool of nostalgists for Vichy France and French Algeria that Jean-Marie, a former troublemaking MP and paratrooper, hammered together in 1972.

And as Marine Le Pen enters middle age, a younger generation is now emerging, in the shape of Marion Maréchal-Le Pen, 24, one of the Front’s three MPs, who is the daughter of Yann, Marine’s second sister. Perky and articulate beyond her years, Marion is already a star. She is said to be closer to the patriarch than Marine because she shares her grandfather’s uncompromising beliefs, opposing gay marriage, for example, while Marine tolerates it.

Also helping keep power in the family is Louis Aliot, one of the party’s five vice-presidents, Marine’s domestic partner – and her paid assistant in the European Parliament. A rugby-playing lawyer and Front militant from Toulouse, Aliot got together with Le Pen after she divorced, first from Franck Chauffroy, a businessman, and then from Éric Lorio, a former Front official and councillor in Nord-Pas-de-Calais.

The Front’s old guard dislike the way that she has “de-demonised” the party, down to details such as banning leather jackets and requiring blazers among the personnel. But Le Pen has imposed her authority since her election as party leader nearly four years ago and scored well in the 2012 presidential race. She has distanced herself from the father who still admires the wartime occupation and she disowns him openly when he reverts to the old sulphur, as he did this summer when he suggested that disease was a remedy for African immigration to France. “Monsieur Ebola can solve the problem in three months,” he said.

He has also taken issue with Marine’s plans for rebranding the party, with the aim of dropping the “Front” label, which conjures up brown shirts and stiff-armed salutes. “Only bankrupt companies change their names. That would be betraying the militants who built the movement,” Jean-Marie said this month.

Tension between father and daughter reached a peak in August after one of his dogs killed Arthemys, her cat, on the Montretout estate. She moved out with Aliot and her three children and they now live in a closed community in nearby La Celle Saint-Cloud.

Yet Le Pen père, who continues to stir trouble as the honorary Front president, is proud of the daughter whom he acknowledges neglecting as a child. “Marine is more shy, less warm, less sentimental than me, perhaps. She is my daughter all the same,” he told Serge Moati, a documentary-maker. “People have tried to break the tie between Marine and me but they don’t manage to.” His daughter has an independent mind but she is refusing to “follow the rule of killing the father”, he added.

A Parisian bourgeoise, child of the 1980s, Le Pen defends her father, though she has jettisoned his retro obsessions with the Second World War, the colonies and race that have landed him multiple court convictions for hate speech. On 20 November, the Paris Appeal Court fined him €5,000 for a pun it deemed a racist insult against the Roma. He had said that, “like birds, they steal naturally”. The French for steal (voler) is also the verb for “to fly”.

Yet, for all Marine Le Pen’s feminine stamp on dad’s nasty party, hostility to immigration remains her stock-in-trade. She has merely shifted the ground, focusing on radical Islam rather than race, lumping together the Muslim immigrant presence and the assault on the nation that is supposedly waged from Brussels by free trade. She says that France is finally waking up to the ruin wreaked by immigration, the euro and the removal of internal EU frontiers. The country needs to reclaim its monetary and territorial sovereignty, she told me.

“Before the total opening of frontiers with the EU, France was a trading nation and rather more so than today . . . From the moment that they put in place the convergence criteria for the euro, our exports collapsed and our imports collapsed. With control of our frontiers, we will just be like 95 per cent of the countries of the world.”

This goes down well in milieux where people would never have acknowledged sympathy for the old man. “Marine talks sense,” is a line you hear in suburban cafés and workplaces whenever the conversation gets around to la crise, the sense of decline that has hung over French life for decades. Saying “I’m with Marine” is easier than voicing admiration for the Front. Blurring lines, the daughter talks less of the Front than her Rassemblement Bleu Marine – “the navy blue rally”, a flag under which her candidates run in local election campaigns.

Middle-class sympathisers liken the FN movement to the US Republican Tea Party, Nigel Farage’s UK Independence Party and the readership of the Daily Mail, yet she is not there yet. The old stigma dies hard. Farage has refused to ally his Ukip MEPs – the other big anti-EU bloc in Strasbourg – with Le Pen’s because of what he calls the Front’s racist DNA. The differences do not stop at the past. Le Pen’s lurch to anti-capitalist populism is the opposite of Farage’s freebooting market ideas. Les Anglo-Saxons are the adversary in the Le Pen universe, while Putin’s Russia is her favoured model. If only France had a patriotic leader who stood up for the nation like Vladimir, she says.

Farage’s rejection upsets Le Pen, but she makes no excuses for refusing to conform to the more civilised manner that, to some, can make him seem unthreatening. “I’ve had long talks with Nigel Farage,” she told me when she was still courting him. “But his Ukip is a young movement which is suffering the same strong demonisation that is applied to everyone that opposes the EU. He is not tough enough yet to resist the demonisation.”

Le Pen’s task is to turn her insurgency into a machine that could plausibly govern. She says she is ready to become prime minister in “cohabitation” with Hollande if he dissolves parliament and the Front wins a majority. She is alone among the party leaders in demanding dissolution, which she says is needed because the most unpopular administration in modern French history has lost public trust. She voices admiration for David Cameron’s promise of an in-out referendum on EU membership, and says that within six months a Prime Minister Le Pen would hold a vote to tell Brussels (as she put it in an interview with Europe 1 radio in October): “Either you reform and you give us back our sovereignty and independence over the currency, or I will propose that France leaves the Union.”

There is little chance of any such thing, given that Hollande has no need to call elections that would be suicidal, and that the Front would have little hope of winning because of the eliminating power of the two-round electoral system and the party’s thin structure. It would need to jump from three MPs to the 200 or so required to secure a working majority. But Le Pen is out to remedy the weakness. Where Jean-Marie never tried to move beyond a protest movement, she and her entourage in Nanterre are weaving networks of activists, anointing candidates, courting business leaders and senior civil servants and trying to win respectability with the thinking classes.

The work at ground level is being waged by Front stars such as Steeve Briois, a 42-year-old who triumphed in March in Hénin-Beaumont, Le Pen’s northern perch, winning the mayoral seat in the first electoral round. Few local people have a bad thing to say about Briois, who is greeted with cheers when he wanders the streets of red-brick terraces and drops in to the market square to chat like any French mayor.

“He’s a nice guy. La Fête de la Musique was great this year, thanks to Steeve,” said Dorothée, a shopkeeper, referring to the popular Midsummer Night party associated with the Socialists since the government invented it in the 1980s.

To clean up the town’s finances, which had been run into the ground by a sleaze-ridden PS council, Briois brought in as his deputy Jean-Richard Sulzer, 67, a Paris University economist and veteran Front policymaker. “It’s excellent being able to put our ideas into practice,” Sulzer told me. “It shows people we can run a clean shop.”

A long-time oddity in the academic world because of his Front role, Sulzer insisted that many colleagues are rallying to the cause. “A substantial number of teachers are going to vote for the Front. They won’t admit it. It’s a perfectly hidden vote but our network of intellectuals is spreading rapidly,” he said.

The party’s chief asset on the intellectual side is Florian Philippot, a 33-year-old who hails from the civil service elite and who is, in effect, Le Pen’s deputy. A disciple of de Gaulle – a figure abhorred by Jean-Marie and the old guard – Philippot is shaping Le Pen’s new doctrines of shoring up the welfare state and defending the poor.

The crossover from “brown to red” is vital for her fortunes. She is doing an excellent job capturing les petits blancs – the dispossessed white inhabitants of the suburbs and small towns – says Pascal Bruckner, a star essayist from the post-1968 era. “The genius of the Front is the way it has taken over the values abandoned by a left that converted to multiculturalism,” he said on television recently. The Front is offering old-fashioned certainties, a lurch back to the imagined golden age of the mid-20th century. This was the era of the “Trente Glorieuses”, the 30 years of growth that are the stuff of fashionable nostalgia, reflected in retro pop songs, comedies set in the 1960s and above all by Le Suicide français, a new, bestselling rant against the evils of modern France by Éric Zemmour, a right-wing essayist.

Le Pen is subliminally promising a return to this imagined golden age that ran up to the mid-1970s. She is forecasting a surge to 3-4 per cent economic growth simply from stopping immigration, slapping tariffs on imports and leaving the euro. Her contempt for Sarkozy, Hollande and what she calls the discredited political classes goes down well. “They have failed. They are bankrupt,” she told a radio phone-in in mid-November. “They didn’t react for decades when our sovereignty passed into the hands of the European Union and we became a vast playground for the multinationals.”

It is perhaps easy to be carried away by the spectre of President Marine. As implausible as it seemed until lately, the big parties are taking the prospect seriously. L’Express news magazine recently published a cover report explaining “Why the worst is possible”. It quoted Bernard Cazeneuve, the interior minister, saying that her victory could no longer be excluded. It is expected that Le Pen will reach the run-off for the presidency in 2017. A recent Ifop poll showed her topping the vote or coming second to the UMP in a notional first-round presidential vote. In all hypotheses, she would relegate Hollande or any other Socialist to third place. Her most redoubtable adversary at the moment would be Alain Juppé, the UMP elder statesman, a former prime minister who is nearly 70. He is eclipsing Sarkozy’s attempted comeback, according to Ifop.

Yet it is unlikely that Le Pen will be able to pull it off. Some calm analysis comes from Jean-Yves Camus, an academic authority on the Front. “If her opponent in the second round is Sarkozy, he wins the match easily, and if it is Juppé or anyone else from the UMP, they will still beat Marine Le Pen,” Camus told me. We are back to the matter of the so-called anti-Le Pen Republican Front. “The question is, if a left-wing candidate reaches the second round, will UMP voters back the Socialist to block Le Pen?”

He thinks that, for all the sympathy on the right for Le Pen, they will flinch from putting her in the palace. “They may back the Front locally, but in a presidential election the question is whether it has the capacity to run the country. The Front does not have the elite necessary to take the controls of the state. It’s as simple as that.”

Le Pen has done a solid job harnessing the nation’s discontent, Camus agrees. “But it’s not very difficult, given the toxic atmosphere that reigns in French politics and the colossal errors being made by her opponents. Marine Le Pen has only to stay in her armchair and watch the news.”

Charles Bremner is Europe editor of the Times