Still a hero of French Socialists despite his decision not to stand, he will co-ordinate the support committees' work.
Mr Delors arrived surrounded by figures from the arts world, academia, sport and the media who had united to form the vanguard of the support group.
All the candidates have been competing for the favours of prominent personalities who then become campaign mascots. The Chirac campaign stole a march with a star-studded soire two weeks ago, which made Jacques Chirac candidate of the moment and showed people were defecting to him from the Socialists. Yesterday, the Socialist Party produced a document with the names of "the first 400 signatories" to its campaign. They included the writer Claude Lanzmann, the film producer Elisabeth Badinter, the commentator and thinker Bernard-Henri Levy, and Jean Fabre, a former French rugby captain.
The plethora of names, and presence of Mr Delors, provided a timely fillip for the Socialist campaign, which seemed in danger of running aground almost as soon as it had been launched. Mr Jospin is in second place, but has stagnated at about 20 per cent of the first-round vote. Meanwhile left-wing votes are going to the personable Communist, Robert Hue, and even to the perennial candidate of the extreme left, Arlette Laguiller.
On the stump, Mr Jospin still makes a positive impression, and his campaigning has hardly begun. But he has ground to make up and the Socialists will not be helped by all the evidence of lying and corruption that has come out of trials involving Socialist officials.