Tokyo Electric Power is Lehman Brothers times 10. It really is too big to fail. The company supplies 29 per cent of Japan’s electricity to more than 2m businesses and 26m households in the Tokyo metropolitan area. Not only is Fukushima Daiichi now out of permanent action, 13 of the company’s 17 nuclear reactors are offline, as are half of its 20 oil-fired thermal plants and both of its coal-fired thermal plants.

Tepco’s loss of power generation – about one-quarter of its normal output – is already having a profound effect, even before the intensely hot summer months when demand surges. The government is expected to exercise a legal provision, not invoked since the 1974 oil shock, to restrict electricity use this summer to just three-quarters of last year’s level. Keidanren, the big business lobby, worries that enforced cuts will damage swaths of industry – railways, pulp and paper, steel, chemicals, breweries, computer chip makers, auto and auto-parts makers all rely heavily on power. It is desperately trying to persuade the government to accept voluntary cuts.

In short, all talk about the earthquake and tsunami affecting only a small part of Japan’s gross domestic product looks optimistic. If power cuts carry on for the rest of the year, or longer, the very heart of Japan’s economy will be on life support.