President Nicolas Sarkozy's chances of re-election this spring will boom if the far right candidate, Marine Le Pen, is locked out of the race, according to a poll published yesterday.

The poll triggered claims from the far right of an "undemocratic" conspiracy by Mr Sarkozy's party, the UMP, to deny Ms Le Pen the 500 official signatures needed to make the first round ballot on 22 April. So far, the National Front (NF) leader has 352 promises from village mayors and elected officials and is struggling to find new sponsors before a 16 March deadline, despite almost 20 per cent support in the polls.

At a rally in Toulose last night, Ms Le Pen said she would not let the "clique" of mainstream parties give her "lessons on democracy...It's not me they're scared of. It's you, the French people, that they are trying to silence."

Centre-right and Socialist politicians said Ms Le Pen was not gathering signatures due to "extreme" and "absurd" statements and xenophobic and anti-European policies. Others claimed she was lying about the number of sponsors in order to seem a "victim of the system".

A poll for the Journal du Dimanche found yesterday that Mr Sarkozy would draw level with Socialist front-runner, François Hollande, if Ms Le Pen was barred from the race. Without her name on the ballot paper, the poll found Mr Sarkozy and Mr Hollande would each attract 33 per cent of the first round vote. If the far right was present, Mr Hollande would score 29.5 per cent, Mr Sarkozy 24.5 per cent and Ms Le Pen 19 per cent.