The woman who could have been President of France steadied herself in the bar of a rocking high-speed train and acknowledged that her ambitions were being thwarted by her conjugal life.

Ségolène Royal had just heard that François Hollande, leader of her embattled Socialist Party and her domestic partner of 25 years, planned to keep his job for another year.

“If he had resigned I would have stood for the job. But I’ll adapt in a consensual spirit,” Ms Royal said, with a flash of the smile that beguiled France.

In keeping with the enigma of the troubled power couple, it was far from clear that she knew of her partner’s plans before he aired them in a morning radio interview.

Still the star of the demoralised Left, Ms Royal, 53, was touring the north to help candidates in parliamentary elections that start tomorrow. The run-off on June 17 is forecast to produce a landslide for the centre-right camp of Nicolas Sarkozy, who defeated Ms Royal by 53 to 47 per cent in last month’s presidential vote.

Ms Royal holds no party post and has abandoned her parliamentary seat of 19 years, but remains president of the Poitou-Charentes region. On the train with journalists, she made clear that she wanted revenge against Mr Sarkozy in the 2012 election. Watching her progress through the Lille area, it was hard to tell that she was no longer the shining hope on the brink of the presidency.

Hundreds turned out for a glimpse of their “Ségo” as she dropped into village halls and community centres.

Earlier, in a theatre in the old coal-mining town of Béthune, Ms Royal basked, eyes closed, in the cheering. “I don’t even have to speak for you to understand me,” she told her fans.

Starting with her strangely triumphant defeat speech on May 6, Ms Royal’s strategy has been to act like a winner. Still an outsider, she is trying to disconcert the party barons, gain leadership of the Opposition and beat Mr Sarkozy next time. She will bid for the leadership next year, she said.

She aims to use her overwhelming popularity with party members to beat Dominique Strauss-Kahn, the pro-market reformer, her chief rival. He and other “elephants”, as the barons are known, hold her and Mr Hollande responsible for the party’s third presidential debacle in a row.

Like the British Labour Party in its wilderness years, the Socialists are still torn between modernisers and old-fashioned leftwingers. They are reeling from the way that Mr Sarkozy has seduced the working class and seized the Left’s high ground. Mr Strauss-Kahn and the other reformers view Ms Royal as “incoherent” and old Socialist at heart. Asked how she would restore credibility, Ms Royal told The Times: “We will not spare our efforts to achieve our renewal.”

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