nPower is the latest energy company to put up its prices this autumn, by 10.4 per cent on top of 9 per cent last November, during a period in which the rate of inflation was a mere 2.8 per cent.

This will add £137 to the average annual dual fuel bill of £1,460.

The company, like others of the Big Six Ugly Sisters, blamed the increase on the rise in wholesale prices and on government-imposed green policies (though the impact of latter is tiny).

David Cameron's answer to this dilemma is for customers to change to another supplier but when they all follow one another in lockstep, fat good is that.

Actually the government itself believes that a huge and continuing rise in energy prices is inevitable, as the Energy Secretary let out of the bag on Monday.

Ed Davey was at pains to sugar-coat the bitter pill of the public subsidy-driven deal with French EDF and Chinese state-owned corporations with warm-sounding assurances, but he gave the game away when he had to admit that the "strike price" - the price at which the government is now contracted to buy electricity from the new nuclear plant at Hinkley for the next 35 years after 2023 - is twice the current market rate and, worse still, will be fully inflation-proofed every year for a third of a century.

So the truth is that the government is convinced that that electricity prices will double in future.

Either it secretly supports this - because in its eyes the market must always rule - or it feels helpless to prevent it. So are endless energy price rises inevitable?

They are not. The companies blame fast-rising wholesale costs as the main culprit, but that's not what the facts show.

In 2008 companies' wholesale costs averaged £495 out of customers' bills averaging £965.

By 2013 wholesale costs had only slightly risen to £575, but customers' bills had soared to an average of £1,325 a year.

In other words, the sharp rise in prices in the last five years was not a result of rising costs in wholesale markets but rather their own profiteering.

Can this be averted within the present oligopolistic market structure?

Probably not, since while an energy price freeze is popular as long as it lasts, when it ends - as Ed Miliband's will after 20 months - there is always the risk of a sudden surge in price catch-ups.

So what is really needed is a fundamental reform of the market structure.

That could mean bringing an end to the current system of vertical integration whereby the big six both generate, trade and supply energy, thus allowing them to manipulate where they make their profits in their own interest at the expense of consumers.

And one or more of the companies could be brought back into public ownership. This could be argued on several grounds - that they have not invested on the scale required to safeguard Britain's long-term energy needs, that they have deliberately bamboozled consumers with a bewildering array of confusing tariffs or that they are a cartel that has extinguished any real competition.

A publicly owned energy company would act as a benchmark serving the national interest rather than the privateers' own short-term self-interest. That would steadily bring prices down.

Michael Meacher is Labour MP for Oldham West and Royton. For more of his writing visit www.michaelmeacher.info/weblog