Japan lurched towards one of the biggest shifts in its postwar political landscape yesterday as Taro Aso, the Prime Minister, called an election that is likely to lead to the defeat of his ruling Liberal Democratic Party (LDP) for only the second time in 54 years.

Mr Aso’s decision, denounced as “mass suicide” by one of his MPs, came after the LDP suffered a humiliating defeat in Sunday’s elections for the Tokyo metropolitan assembly. The opposition Democratic Party of Japan (DPJ) won 54 out of 127 seats in the Tokyo assembly, compared with 38 seats for the LDP which, even with the support of its coalition partner, New Komeito, lost its majority. After meeting his party lieutenants, Mr Aso announced an election on August 30.

The probability of devastating defeat — with the loss of many parliamentary seats — may yet foment an anti-Aso rebellion, or even the break-up of the LDP, as desperate MPs desert to other parties or run as independents. Mr Aso, however, insisted that he would remain at the helm even as he heads, seemingly inexorably, towards electoral defeat.

“I know there are various opinions,” he said. “But I will work hard, clenching my teeth.”

He may be hoping for salvation in the form of another scandal within the DPJ. In May, Ichiro Ozawa, the DPJ’s leader, resigned after a fundraising scandal and his successor, Yukio Hatoyama, faces embarrassing questions after admitting making donations to himself under the guise of external fundraising.

“One never knows until an election what will happen,” Mr Aso said. “This time is no exception. We must fight even in a difficult situation.”

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