UPDATE 1-Motor racing-Mosley says Todt his ideal successor

* Mosley to stand down as FIA president

* Backs former Ferrari boss Jean Todt as successor

* Vatanen only confirmed candidate so far

(Adds detail, quotes, byline)

By Alan Baldwin

LONDON, July 15 (Reuters) - Max Mosley backed former Ferrari boss Jean Todt as his ideal successor on Wednesday after ending speculation that he would seek a fifth term as head of motorsport's world governing body.

The International Automobile Federation (FIA) president wrote to all member clubs saying he had received almost 100 messages of support from within the organisation but had decided to stand down anyway.

Mosley, 69, said a new commercial 'Concorde' agreement for Formula One was close to being finalised while new teams had been brought in and costs reduced.