If Taro Aso, Japan’s prime minister, leads his Liberal Democratic party to victory in the general election he plans to call for August 30, he will win glory for ­presiding over one of the biggest turnrounds in the once-mighty LDP’s 53-year history.

If, as polls suggest is ever likelier, the election instead delivers power to the opposition Democratic party, Mr Aso is at risk of going down in Japanese political annals as the turkey who voted for an early Christmas.