A weekend of strife has brought the French Socialist Party to its knees, setting the stage for a leadership showdown this week between two female enemies: Ségolène Royal, the former presidential candidate, and Martine Aubry, a former leftwing Cabinet minister.

The pair emerged in front yesterday from the wreckage of a party conference at Rheims that collapsed into a festival of loathing between Ms Royal’s upstart camp and an old guard now backing Ms Aubry, 58.

Ms Royal, 55, finished second in last year’s presidential election but, for much of the party executive, she remains a lightweight usurper with an evangelical streak. After being drowned out by jeering at the conference, she appealed in vain for an end to the internecine bloodshed. “We will have to forget all the unpleasant and at times violent words, erase them and one day forgive each other,” she said.

The former presidential contender is popular at the grass roots as a charismatic modern politician – unlike Ms Aubry, who is seen by many as an old-guard warhorse.

“I am ashamed of our party,” said François Hollande, outgoing leader and former partner of Ms Royal, after cancelling the closing speech at a conference that was supposed to anoint a chief and relaunch the opposition to President Sarkozy, who is enjoying a new streak of popularity.

Ms Aubry, Mayor of Lille and architect of France’s 35-hour working week, appealed to the party to come to its senses. “The French people do not hate us, but we have let them down,” she said. “We could perhaps be facing the end of the Socialist Party.”

The party’s 200,000 members will now vote on Thursday to choose from three candidates: Ms Royal, president of Poitou-Charentes; Ms Aubry, the daughter of Jacques Delors, a former President of the European Commission; and Benoît Hamon, 41, a leftist MEP who is a distant third. A run-off will be staged on Friday if no one wins an absolute majority.

Whoever wins, the party seems set for a long civil war because the gulf between the Royal camp and the rest appears unbridgeable.

Ms Royal emerged as the most popular in a preconference ballot by members, but Ms Aubry is hoping this week to rally behind her the majority that does not support the failed presidential candidate. The way was cleared for their showdown when Bertrand Delanoë, the Mayor of Paris and an early favourite for the leadership, pulled out yesterday.

Many party supporters have lost patience with the failure of the centre-left Opposition to seize the occasion of the economic crisis to regain the initiative. Some are switching their affections to Olivier Besancenot, a popular Trotskyite postman, who is about to launch a New AntiCapitalist Party.

The Socialists have been torn between their two historic wings – pro-market social democrats and old-school Marxists. All the candidates have shifted leftwards with what even Mr Sarkozy calls the crisis of capitalism, but Ms Royal has peformed the biggest leap and is now casting herself as a near-revolutionary. In a closing speech yesterday she rallied her supporters with an attack on “the fundamentalists of the financial markets who call on the state for help like you summon a servant to mop up the mess after a drunken party”.

– France faces a week of disruption from transport and public sector strikes, as unions wage a series of separate campaigns against Mr Sarkozy’s labour reforms.

Power games

1971 François Mitterrand takes over Socialist Party

1981 Mitterrand elected President, restoring leftwing government for first time in 30 years

1995 Jacques Chirac, centre-right candidate, elected President

1997 Lionel Jospin and his Socialist Party win parliamentary power

2002 Jospin eliminated in first presidential round by Jean-Marie Le Pen. Chirac reelected

2007 Nicolas Sarkozy, centre-right candidate, trounces Royal

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