Prosecutors have begun closing in on a key figure in the dirty tricks scandal that has rocked the French government for the past three weeks.Officials have authorised the arrest of the nation’s spymaster-General, Philippe Rondot, who has ignored an injunction to testify in the affair. It is believed Rondot can throw light on how a list of alleged account holders at the Clearstream bank in Luxembourg, including several senior political figures, was sent anonymously to investigators. Prime Minister Dominique de Villepin has been accused of using the list to discredit his political rival, Interior Minister Nicolas Sarkozy. He denies the claims. The affair has caused unprecedented divisions in the government and placed Villepin’s position under intense scrutiny. The man who has confessed to sending the list, the executive vice-chairman of the European space firm EADS, Jean-Louis Gergorin, faces dismissal proceedings after the company said it intended to fire him. Sarkozy is seen as a front-runner in next year’s presidential election. Villepin is also believed to harbour presidential ambitions.