He is back. Or rather, some say, he never went away. Nicolas Sarkozy announced on his Facebook page yesterday that he was returning to politics to create a “new” and “vast” 21st-century political movement which will “transcend traditional political divisions”, and he proposed a “new project” for France.

More prosaically, he is running for the vacant presidency of his old centre-right party, the Union pour un Mouvement Populaire (UMP). He intends to “transform” the UMP into a new Sarkocentric movement in three months to freeze out rival candidates for France’s presidency in 2017.

Despite a tangle of a half-dozen legal investigations into his activities, Mr Sarkozy’s comeback was long expected. He will make his plans clearer in a television interview tomorrow night and a speech in Lille next week.

Friends compare Mr Sarkozy to General Charles de Gaulle, who returned from self-imposed exile in Colombey-les-Deux-Églises in 1958, or to Napoleon who escaped from enforced exile on Elba to restore the Empire in 1815.

Critics say Mr Sarkozy, 59, is more like the Count of Monte Cristo, determined to get revenge on those who have belittled and thwarted him.

In private, he is especially vicious about President François Hollande, the man who turned him out of the Elysée Palace in 2012. The former President says Mr Hollande should not be defeated but hounded out of office and “tarred and feathered”.

At the same time, Mr Sarkozy’s friends have let it be known that the born-again Sarko plans to be a gentler, more inclusive leader, less impetuous, less self-regarding and more focused on the reforms France needs. He is returning, they say, not from personal ambition or from a spirit of revenge but because he is the only man who can rescue France from the menacing rise of Marine Le Pen’s cosmetically laundered, far-right Front National.

Either way, Mr Sarkozy has been forced to declare his hand early and to take an enormous risk (against, it is reported, the wishes of his wife, Carla Bruni-Sarkozy). He will run in November in an internal party election for the vacant presidency of the UMP – a job that he mocked as beneath his ex-presidential dignity a year ago.

In pictures: Nicolas Sarkozy through the decades Show all 12 1 /12 In pictures: Nicolas Sarkozy through the decades In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Nicolas Sarkozy looks on before the meeting with King Juan Carlos of Spain at the Zarzuela Palace on 27 May 2014 in Madrid In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Former French president Nicolas Sarkozy leaves 'La Petite Maison' in Nice, southeastern France, on 27 September 2013 after a private conference in Cannes In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy France's outgoing president Nicolas Sarkozy shakes hands with France's president-elect Francois Hollande, next to France's outgoing First Lady as they are about to leave the Elysee presidential Palace after the formal investiture ceremony between Francois Hollande and his predecessor Nicolas Sarkozy, on 15 May 2012 in Paris In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy President and right-wing ruling party Union for a Popular Movement (UMP) candidate for the French 2012 presidential election Nicolas Sarkozy gives a speech during a campaign meeting in Saint-Pierre in the French overseas island of La Reunion, on 4 April 2012 In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Former France's president Nicolas Sarkozy and his wife Carla Bruni-Sarkozy leave the Elysee presidential Palace after the formal investiture ceremony between France's president-elect Francois Hollande and his predecessor Nicolas Sarkozy on 15 May 2012 in Paris In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy French Interior Minister and leader of the French ruling Conservative party UMP (Union for a Polpular Movement) Nicolas Sarkozy greets British Conservative party leader, David Cameron prior to a meeting in Paris on 6 January 2006 In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy French interior minister and powerful head of the ruling UMP party Nicolas Sarkozy pronounces a statement in the high chamber of French Parliament focused on his general policy on 8 June 2005 in Paris, few days after his return to government office In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Nicolas Sarkozy in Brussels on 3 May 2004 In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Nicolas Sarkozy, then minister of Interior and French President Jacques Chirac at Elysee palace in Paris on 10 May 2002 In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Nicolas Sarkozy, head of the neo-Gaullist Rally for the Republic (RPR), waves during a rally in Dijon on 4 June 1999 ahead of the 13 June European elections In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Nicolas Sarkozy in campaign for the Legislatives of 1986 In pictures: Nicolas Sarkozy through the decades Nicolas Sarkozy Nicolas Sarkozy participates in a demonstration in Paris, 14 April 1976

He will do so partly to try to rescue a party which has been torn apart by financial scandals, largely of his own making. He will do so in an attempt to re-establish himself as the de facto leader of the opposition before his credibility is destroyed by one or more of the cat’s cradle of criminal investigations in which his name has appeared.

He will do so mostly to try to derail dangerous rival Alain Juppé, the popular but ageing former centre-right Prime Minister. Mr Juppé, 69, announced last month he will run in an “open primary” planned by the UMP in 2016 to select the centre-right candidate for the presidential election the following year.

Mr Sarkozy remains heartily disliked by more than 60 per cent of French people. He is hero-worshipped by grass-roots members of the UMP, especially the younger ones.

He would struggle to beat Mr Juppé in a primary open to all French electors. He will easily win the internal election for party president in November.

Mr Sarkozy then plans to, in effect, abolish the UMP and start a new party with a new name. In his brief statement on his Facebook page, he said this would be a “new and vast political gathering [he used the Gaullist word rassemblement], which will go beyond the traditional [left-right] divisions, which no longer have any connection with reality”.

Since the new party will be built in Mr Sarkozy’s image, there will be no need – he will argue – for a primary election in 2016. Mr Juppé will be, as Mr Sarkozy curtly says in private, “no longer an issue”.

The strategy could work. Mr Sarkozy could become the first defeated president of the Fifth Republic (post 1958) to run again. Despite the long list of legal investigations involving his activities before, during and after his 2007-12 presidency, he could return to the Elysée Palace.

Mr Hollande, and the entire left, is desperately unpopular. A large majority of French people – faced with a second-round choice in 2017 between Mr Sarkozy and Ms Le Pen – would almost certainly vote for the former President.

All the same, Mr Sarkozy is taking an enormous risk, both for himself and for France.

He has already been placed under investigation for trafficking his influence to shape a decision in France’s highest court. Investigations continue into, among other things, his alleged political funding by the late Libyan dictator Muammar Gaddafi and the misuse of UMP party funds to breach the limit on spending on his 2012 presidential campaign.

By returning to politics, Mr Sarkozy hopes to strengthen his argument that all such investigations are politically driven. He could, however, saddle France with a de facto leader of the opposition who is in profound legal trouble.