The leader of the Democratic Party of Japan, Seiji Maehara, and two other senior DPJ officials resigned on Friday over a misfired attempt to discredit the ruling party, leaving the long-suffering opposition group in disarray.

One of the party?s lawmakers had accused the son of a senior official of the ruling Liberal Democratic party of receiving money from Takafumi Horie, the disgraced internet entrepreneur.

An email shown in parliament to back up the claim of alleged shady dealings between the LDP and Livedoor, the internet company formerly run by Mr Horie, was later revealed to be false.

Mr Maehara, who only assumed the party leadership after the DPJ?s pummelling in last September?s snap election, Yukio Hatayama, the party?s secretary general, and Hisayasu Nagata, who presented the fake email to parliament, all said on Friday they would quit over the affair.

Mr Maehara said: ?It was necessary for me to make a political decision over the email fiasco. I bear the heaviest responsibility.?

The incident demonstrates the resilience of Junichiro Koizumi?s government, which had initially been tarnished by its association with Mr Horie, who faces charges of helping to window-dress Livedoor?s accounts.

The Koizumi government approached Mr Horie to run for parliament on an LDP ticket, although he eventually stood in September?s election as an independent.

But as has happened before, the scandal rebounded on the opposition, which many consider too politically na?ve to ever seize power. The LDP has governed for all but nine months of the past 60 years.

Mr Koizumi?s government once wobbled when it was revealed that half his cabinet had skipped pension contributions. But on that occasion too, the scandal boomeranged on the opposition causing the resignation of its then leader Naoto Kan.

Possible candidates to succeed Mr Maehara include Mr Kan, who has held the position twice before, and Ichiro Ozawa, a political wheeler dealer who turned down the post when Mr Kan resigned. A ballot will be held next month.

The opposition party has until next summer to regroup in time for upper house elections in which the LDP is, theoretically at least, vulnerable to a setback.

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