Japan’s interior minister quit on Friday, dealing a heavy blow to the administration of Prime Minister Taro Aso and exposing deep divisions within the ruling Liberal Democratic party in advance of a potentially pivotal general election.

Kunio Hatoyama, previously a strong ally of Mr Aso, said he resigned because the prime minister had made the “wrong decision” in a bitter dispute about management of the postal system that had divided the cabinet and aggravated long-standing differences between the LDP’s conservative and reformist wings.