The former leader of a Japanese doomsday cult who was sentenced to hang for masterminding a deadly nerve gas attack on the Tokyo subway system in 1995 has filed a petition for a retrial, the Tokyo District Court said yesterday.

Shoko Asahara, 53, was found responsible for gassings on Tokyo rush-hour subways that killed 12 and sickened thousands, and was sentenced to death by the Tokyo court in February 2004 for murder and attempted murder.

The gassings with the lethal nerve gas sarin injured about 5,500 people, some permanently, and stunned the public, shattering Japan's image as a haven of public safety.

An appeal by Mr Asahara, whose real name is Chizuo Matsumoto, was rejected by Japan's Supreme Court in September 2006 and he is on death row.

A spokesman for the district court said the petition for retrial had been filed on Monday.

The spokesman declined to say how long it would take to make a decision or to comment on other procedural matters, but the Yomiuri newspaper said the government did not usually carry out executions while a retrial petition was being considered.

The newspaper said the petition was based on what Mr Asahara's lawyers considered new evidence from testimony by a senior member of the cult that the attacks had been carried out against their leader's wishes.

At its peak, the cult boasted at least 10,000 members in Japan and overseas, including some who had studied at elite universities.