Hardened observers of Japanese politics may be forgiven a wry smile when they hear that the mighty Liberal Democratic party is heading for historic defeat at the next general election. They have heard it all before, and somehow the LDP has (almost) always found a way to cling on to power. It has now been in office for all but 11 months of the past 53 years.

Yet rather like an ageing overweight sumo wrestler, it is hard to see how the party can avoid being tripped up when the country goes to the polls on August 30. It has run out of ideas, exhausted its leadership options, and is reduced to interminable faction-fighting. Sunday’s humiliating defeat by the opposition Democratic Party of Japan in the Tokyo municipal elections is seen as a clear portent.