Segolene Royal was well beaten by Nicolas Sarkozy in the 2007 presidential election campaign, but her political ambitions remain undimmed.

Bidding for leadership of the French Socialist Party, she has inspired both a devoted following, and trenchant opposition.

Even if she wins, she will struggle to unite a party dismissed in some parts of the French press as "ungovernable".

She is popular among grassroots supporters, and has promised to give the party an "unshakeable future".

But she still has many critics among the party grandees - the so-called elephants - who say she is too lightweight and would lead the party in the wrong direction.

Damaging split

And it is not only ideological opposition she faces - in one case in particular, it's personal.

Ms Royal is hoping to take over the party leadership from her former partner, Francois Hollande.

They were once known as the party's "golden couple", but split last year, around the time of the election itself, after spending nearly 30 years together and having four children.

While they have insisted they are still friends, Mr Hollande has refused to support her politically.

Despite her overtures - publicly praising Mr Hollande and his record - he threw his weight behind Bertrand Delanoe, mayor of Paris, for the party leadership.

The Socialist Party itself has wrestled with bitter infighting since 1995, when France's last Socialist president, Francois Mitterrand, stepped down.

Its annual convention in mid-November ended in disarray after failing to reach a consensus on the three candidates, despite Ms Royal winning a pre-convention ballot with 29%.

Ms Royal has been increasingly leaning to the left, insisting that economic liberalism and socialism are incompatible, say correspondents.

At the annual conference, held in Reims, Ms Royal pleaded for unity, saying the party would "have to forget all the unpleasant and at times violent words, erase them and one day forgive each other".

Young ambition

Born in 1953 in Senegal, in what was then French West Africa, Ms Royal grew up one of eight children of an authoritarian former artillery officer.

Jacques Royal brought his family back to France in the early 1960s, and life for the Royal children near Epinal in the Vosges was largely unhappy.

Segolene struggled to pursue further education, with her father believing women did not need it. However, he was proud of his daughter's accomplishments at school.

She gained admission to the elite Paris Institute of Political Studies (IEP), where she graduated in economics and went on to study at the influential Ecole Nationale d'Administration (ENA).

According to journalist Daniel Bernard's biography, Madame Royal, the future politician was rebelling against her conservative milieu from the age of 12, questioning why women should have fewer rights than men.

In 1972, her rebellion took legal form when she sued her father for refusing, after his wife left him, to divorce her and provide for the family's upkeep and the education of the children.

She did not win the case until 1981, just a year before her estranged father's death from cancer.

Into politics

At ENA, the traditional "finishing school" for France's senior officials, Ms Royal met Francois Hollande. Mr Hollande now leads the Socialists and was himself seen last year as a presidential candidate.

Ms Royal graduated in 1980 and, along with Mr Hollande, became an adviser to Socialist President Francois Mitterrand.

Elected an MP for the Deux-Sevres constituency in western France in 1988, she is currently president of the Poitou-Charentes regional council.

She served as minister for the environment from 1992-93, and later served as junior minister for education (1997-2000) and junior minister for family and childhood (2000-01).

When she declared her hand for the presidential nomination in 2007, some of the most cutting remarks were made by her own party colleagues.

Laurent Fabius, who ran against her, publicly asked who would look after her children if she went for the presidency.

Ms Royal was blamed for a presidential campaign that was seen as lacklustre and gaffe-strewn.

However, she is a confident campaigner who can inspire genuine popularity, and few will deny she has proven herself as a fighter through her career.