He has ridiculed doctors, mocked the mentally ill and made light of wartime atrocities, but this time Taro Aso may have taken things too far: the Prime Minister of the world’s fastest-ageing nation has condemned Japan’s elderly as a bunch of “hobbling malingerers”.

Having shattered a sacred taboo, the nationalist Mr Aso, who is 68, added: “I pay my taxes, so why should I pay money for people who laze around eating and drinking and never do anything?”

Members of Mr Aso’s own party told The Times that the attack on seniority and ill-health was “completely irresponsible” in a country where one in five voters is over 70 years old, where the healthcare system is in crisis and a general election is looming. “He seems to be saying that old people should feel guilty for visiting the doctor,” said one ruling coalition MP. “He must have said it without realising how many people that would upset.”

Others believe that the comments were entirely predictable, given Mr Aso’s previous form. His attack on old people for their lack of exercise and for “always tottering off to the doctor” was blurted out during a ministerial meeting on the economic crisis and marks probably the most spectacular gaffe of a political career strewn with increasingly baffling clangers.

Doctors, he said recently, tended to lack common sense; Japan, he declared on another occasion, should make itself attractive to “rich Jews”. He was once made to apologise for a joke about people suffering from Alzheimer’s, and quipped to victims of a flood that it was lucky for everyone that the city nearby had not been hit.

In the run-up to his party leadership election in September, Mr Aso admitted that he had been advised to bite his tongue whenever he was gripped by the urge to blurt. Mr Aso briefly apologised yesterday, telling reporters he was sorry if his comments “offended people who are suffering illnesses”.

Yukio Hatoyama, the leader of the opposition, seized upon Mr Aso’s latest blunder as evidence that the former Olympic clay pigeon shooter may not be quite suited to the job - a view he shares with an increasing number of political commentators and newspaper leader writers in Japan. “I can’t help but wonder whether such a person is really fit to be Prime Minister,” said Mr Hatoyama.

The ruling Liberal Democratic Party already faces heavy criticism over mismanagement of the low birth-rate issue, the creaking failures of the health insurance programme and the loss of more than 50 million individual pensions records.

Mr Aso, the colourful scion of one of Japan’s most powerful political dynasties, has led the country for two months since the resignations of his two predecessors, Shinzo Abe and Yasuo Fukuda. As a mere inheritor of the Prime Minister’s position, Mr Aso has spent the past eight weeks watching his popularity evaporate in a cloud of scandal and mismanagement.

He has generated plenty of political capital from his supposed love of pop culture: he has campaigned in parts of Tokyo where young comic-book obsessives gather and continually touted the overseas success of Japanese comics as an example of “soft power”.

But in a rare public appearance last week, Hayao Miyazaki, the Oscar-winning animator and Japan’s most famous cartoonist, said that Mr Aso was an “embarrassment” who should keep his reading habits to himself.

Unwise words

— At a lecture in Takaoka city, talking about the relative prices of rice in Japan and China, Mr Aso, right, said: “Which is more expensive, Y78,000 and Y16,000? Even someone with Alzheimer’s could understand that”

— Concerning doctor shortages: “It is very difficult to secure sufficient doctors for hospitals. A lot of them have no common sense”

— Speaking at Tokyo University on the forced change of Korean and Chinese surnamesduringJapanese imperial rule: “Korean people wanted Japanese surnames”

— Addressing the compulsory education implemented during the colonisation of Taiwan: “Our predecessors did a good thing”

— During a lecture at Nagasaki University on why Japan would be trusted to broker peace in the Middle East: “We Japanese have yellow faces”

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Brüno toned down for 15 rating