Marine and Jean-Marie Le Pen fight over French National Front

Forget Ed and David, Bill and Hillary, George, George W and Jeb.

For anyone fascinated with dynastic politics, the relationship between Jean-Marie and Marine Le Pen is the gift that keeps on giving.

And it's been particularly generous in recent weeks. The 86-year-old founder of France's National Front (FN) has rarely been out of the headlines - or the thoughts of his daughter, the party's current leader.

But not in a good way.

"I had a knot in my stomach every time I heard that Jean-Marie Le Pen was giving an interview," Marine Le Pen told Le Parisien last week.

"I'm sleeping better now than I have for some time."

It took an act of political parricide for her to murder sleeplessness.

Earlier this month, Marine Le Pen suspended her father from the party he founded in 1972 and stripped him of his post of honorary president.

Marine Le Pen and her father in 1974

She'd already admonished him last year, after he included a well-known Jewish singer in what he called an "ovenload" of artists, but when he recently repeated his notorious comment (for which he'd been prosecuted) that the Nazi gas chambers were "a detail of history", she decided that enough was enough.

In reaction, her father threw his toys out of the pram, suggesting that his daughter should change her surname and threatening not to vote for her in the 2017 election.

He appears to have changed his mind about that for now, but he might change it again. It's been hard to keep up. He's also announced that he's forming a new faction within the party.

Underneath the fast-moving family drama is a longer-term question: can the FN maintain its march from the fringes of the French political system to the very centre of the French Republic? Can an insurgent force become the party of power, not through a revolution, but through the ballot box?

To a certain extent, of course, it already has.

I was a student in France in the mid-1980s, when the FN made its first breakthrough in national elections.

Two years after securing 10 seats in the European Parliament, the party won almost 10% of the vote in the 1986 French parliamentary elections - and 35 seats in the National Assembly.

Jean-Marie Le Pen was no longer a sinister-looking fringe candidate with an eye patch, but an eye-catching politician, giving tub-thumping speeches that warned of the threat from mass immigration.

The French establishment closed ranks against him; keeping him at a distance, treating him like an unpleasant smell that was best ignored. It didn't work.

Inconveniently for the established parties, more and more French voters began to find his analysis and his populist, patriotic appeals rather attractive.

Neither the storm created by his gas chamber and other anti-Semitic comments nor a power struggle, which split the party in two, brought an end to his career.

In 2002, I was the BBC's Paris Correspondent during what was Jean-Marie Le Pen's high watermark: his unexpected second place in the first round of the presidential election.

As in the UK this year, pollsters and, mea culpa, journalists did not identify what the French electorate was thinking.

Clothes pegs

The least shy of leaders had attracted what might now be called "shy" Front National voters.

Two weeks later, Socialist supporters - deprived of a left-wing candidate in the run-off - placed clothes pegs (some metaphorical, some real) on their noses and voted for the centre-right candidate, Jacques Chirac; a politician who had once complained of the "the noise and smell" of immigrant households.

The FN was unable to build on this success.

Mr Le Pen's vote dropped in 2007, and in 2010, he announced he was standing down as party leader.

Enter, stage right, his youngest daughter, Marine, who was elected to succeed her father in 2011.

She soon set about a process of "detoxification"; weeding out the party's more xenophobic elements in order to broaden its appeal.

Marion Marechal-Le Pen has been an MP since 2012 and is the honorary chairman of the FN

Out went her father's circle, in came a new generation; indeed, new generations. Her 25-year-old niece - Marion Marechal-Le Pen - is the party's rising star. At 22, she became the youngest elected MP in modern French history.

Although opposition to mass immigration and "Islamification" are still high on the party's list of policies, when I met her in her office, towards the end of 2011, Marine Le Pen was keen to emphasise other threats to the French way of life: globalisation, the EU and the euro.

Paternal politics

It was this approach, she assured me, in her breezily confident manner, that would see her elected president the following year.

She wasn't, but her strategy bore fruit. In the 2012 election, Marine Le Pen came third, but with a higher percentage of the vote than her father got in 2002.

In last year's European elections, the FN topped the polls - the party's first victory in a national election.

So, was this a moment for paternal pride? Not exactly.

"Detoxifying" the party may have made it more electable, but it also represents a repudiation of Mr Le Pen leadership.

Marine Le Pen

• Born 5 August 1968

• Full name Marion Anne Perrine Le Pen

• Youngest daughter of FN leader Jean-Marie Le Pen

• In 1976, she survived a bomb attack on the family as they slept in their beds

• Trained as a lawyer

• She joined the FN in 1986, joined its executive committee in 2000 and was a vice-president for eight years from 2003

• Became president of the FN on 16 January 2011

• She stood in the 2012 French presidential election, finishing in third position behind Francois Hollande and incumbent president Nicolas Sarkozy

So, the man who made his reputation by railing against threats from abroad has increasingly turned his fire on the enemies within, the advisers he blames for leading his daughter astray.

As he made clear in a recent interview in the Financial Times, he doesn't see toxicity as a poison to be removed but as the very lifeblood of the party.

"If you stop being the devil, if you 'detoxify', then you become the right wing of the centre right," he said. "There is no longer a raison d'etre for the FN."

Or perhaps, more worrying for him, there is no longer a raison d'etre for Jean-Marie Le Pen.

Just look at the poll numbers.

According to a recent survey by the BVA polling company, Jean-Marie Le Pen's support among the party faithful has dwindled to single figures, even as his daughter's has soared past 90%.

And it doesn't stop there. Last month, she was named one of Time magazine's 100 people of the year.

As the party has become part of the mainstream, it has begun treating its founder as the French establishment has always done: an annoying smell it would rather do without.

Except the FN hasn't really become part of the establishment.

Jean-Marie Le Pen

• Born 20 June 1928

• He was FN's first leader when it was founded in 1972

• He has run for president five times

• In 2007, he finished fourth, at the age of 78 years and nine months - making him the oldest candidate for presidential office in French history

• He led the party until January 2011, when his daughter Marine took over

• Outspoken and controversial, he is often nicknamed the "Menhir", due to his "granitic nature"

• On 4 May, he was suspended from FN after failing to attend a party disciplinary hearing for describing the gas chambers used in concentration camps during the Holocaust as a "detail" of history

• Holds a seat in the European Parliament and a post as a regional councillor in the south of France

When I was in Paris in January, reporting on the aftermath of the Charlie Hebdo and Jewish supermarket attacks, I was struck by the way that Marine Le Pen was still being sidelined from the national conversation.

As more than a million people marched through the streets of Paris on the Sunday after the attacks, in a show of republican solidarity, she was notable by her absence.

The politician who might come top in the first round of the 2017 presidential election hadn't been invited.

Perhaps she prefers it that way. The outsider status has served her well so far.

And perhaps she's not been entirely unhappy with her father's interventions, which paint her in a more mainstream light.

Intentionally or not, Jean-Marie Le Pen is part of the policy of "detoxification" he apparently despises.