Junichiro Koizumi, the former Japanese prime minister whose colourful style and attacks on his own party turned him into the country's most influential leader in a generation, is to retire from politics two years after leaving office.

Mr Koizumi, 66, told supporters he would not stand for parliament in the next general election, which could be called as soon as next month. The decision goes against the usual practice among Japanese leaders of staying on, sometimes for decades, as backroom power-brokers. Mr Koizumi endorsed his son Shinjiro, 27, to run in his home district in his place.