The leader of the far right National Front party has been abandoned by yet another ally, this time Jean Marie Le Chevallier, the mayor of Toulon, who is one of his oldest political friends.
Mr Le Pen has been caught in Belgium with a small ar- senal of dangerous weapons in the boot of his car. His position in the opinion polls is slipping close to the point where he could lose all credibility as a force in French politics.
As if this were not enough, a court began hearings yesterday to decide who has the legitimate right to the National Front's name, symbol and cash. If Mr Le Pen loses, he could be forced to share all three with Bruno Megret, the long-time second force in the NF, who set up his own rival party, the National Front National Movement, in January.
The breakaway party has difficulties of its own. After rising to 6 per cent in the polls - 1 per cent above the mark that it must reach to scoop seats and public subsidies in the European elections in June - Mr Megret's movement has melted back down to 4 per cent.
But Mr Le Pen's "official" National Front is scarcely doing better. The most recent surveys give the NF only 6 per cent, a third of its score in the polls before the split. If confirmed at the European election, this would be the xenophobic and ultra-nationalist party's lowest score for 19 years.
Mr Le Pen, 70, is mani- festly rattled and behaving erratically, even by his own standards. When Belgian police found a loaded semi- automatic rifle, 50 cartridges, and two tear gas grenades in his car in Brussels, he claimed to have been the victim of a sting operation and railed at a local television crew in an insulting, mock-Belgian accent.
The defection of Mr Le Chevallier, the mayor of Toulon - who has declared himself an independent - is especially damaging to Mr Le Pen. The two had been friends for 24 years and political allies for 15 years. Toulon was the jewel in the NF's crown, the largest town it had ever won.
The mayor's defection reduces the number of town halls under Mr Le Pen's control to one - Orange in the Rhone valley. Two other NF-controlled towns, in the Marseilles outer suburbs, have gone with Bruno Megret, as have more than half of all the party's local councillors nationwide.
Mr Le Chevallier said that he was quitting the NF because he could no longer tolerate Mr Le Pen's unpredictable behaviour and his inability to "share power".
The two men are said to have fallen out several years ago, partly over the increasing influence of Mr Le Chevallier's ambitious wife, Cendrine. Mr Le Pen, it is reported, has not spoken to Cendrine Le Chevallier since 1995.
The mayor of Toulon has, so far, refused to join forces with Mr Megret, whom he detests. It is thought more likely that he will rejoin the "traditional" right, from which he defected to join Mr Le Pen in 1983.