Nicolas Sarkozy’s hopes of running for a new French presidential term in 2017 faced a crucial first test yesterday as members of his crisis-ridden conservative UMP party voted for a new leader.

The online vote, which the former head of state is expected to win, was slowed on Friday evening by a cyber attack on the election web site, but voting continued yesterday and a result was expected in the evening.

Sarkozy won the French presidency in 2007 but has watched impatiently from the sidelines since losing to Socialist François Hollande in 2012.

He is favourite to be named UMP chairman but knows only a convincing win will deter party rivals from emerging to challenge him for the presidential ticket.

“A result below 70 per cent would be in fact a defeat for him, because he is so much the charismatic saviour, that’s how he wants himself to be seen,” Dominique Moisi of the French Institute for International Relations told Reuters TV.

“Less than that score would not do, and would be used by his opponents as absolute proof that his return is a failure.”

With Hollande’s ratings sent to record lows by tax rises and a failure to tackle unemployment, the Opposition conservatives should be flying high. Economic data has shown the country’s jobless rate in a series of record highs and consumer spending in the doldrums.

But the UMP has long been riven by leadership squabbles and is mired in a legal inquiry into alleged funding irregularities, while some of its voters have been lured away by a resurgent far-right National Front led by Marine Le Pen.

A political brawler who polarises French opinion and makes no secret of his dim view of Hollande, Sarkozy stormed back in September with a right-wing platform aimed at winning voters from Le Pen and re-founding his 12-year-old party.