Public broadcaster says prime minister has made decision to avoid divide within his Liberal Democratic party

Japan’s prime minister, Shigeru Ishiba, is to resign less than a year after taking office, throwing the country’s politics into turmoil and setting in motion a potentially messy contest to replace him as leader of the ruling Liberal Democratic party (LDP).

The softly spoken centrist has presided over two disastrous elections since being elected to lead the LDP last autumn. In October, the party and its junior coalition partner Komeito lost their majority in the lower house and met the same fate in upper house elections this July.