Taro Aso, Japan’s beleaguered prime minister, is facing increasingly open rebellion from within his long-ruling Liberal Democratic party as fears grow among senior members that they are heading for a historic defeat at a looming general election.

Yasufumi Tanahashi, a former minister, on Friday added his voice to calls for Mr Aso to step down in time for the LDP to choose another president to lead it into the election, which must be held by October.