Inflation is set to leap ahead next month, making it harder than ever for the Bank of England to cut interest rates again in the near future, due to a change in the way National Statistics accounts for the ups and downs of gas and electricity bills.

In the past NS has trickled in increases - or cuts - in utility prices over four months on the grounds that householders notice them only when their meters are read, or estimated.

But yesterday the statistics office said it will feed changes into its calculation of inflation from the day that utility companies say they take effect. As a result price rises of 15 per cent or more that would otherwise have been fed through gradually into the official inflation numbers between now and May, will all appear up-front in full when NS publishes its February figures next month.

Yesterday NS's January numbers showed that year-on-year inflation picked up to 2.2 per cent last month, measured by the Govern-ment's chosen consumer prices index. This showed prices down by 0.7 per cent on December overall, but this was less than the seasonal drop in January last year.

This included the full impact of increases of 12.7 per cent for electricity and 17.2 per cent for gas announced by npower on January 4.

But fewer than one household in eight buys its fuel from npower, so the impact next month of subsequent increases by British Gas, Scottish Power, EDF and e.on will be much greater.

At Birmingham Chamber of Commerce and Industry, Charlotte Ritchie, head of policy, highlighted the pressure of inflation on businesses whose profit margins are being squeezed by rising food and energy prices.

"Businesses feel that there is still scope for a further quarter-point cut in March," she said.

"High street sales figures for January were stronger than expected and will make it more difficult for the Bank of England's Monetary Policy Committee to vote for further interest rate cuts. Upward inflationary pressures have already prevented the Bank from making large-scale cuts.

"The Bank is right to avoid panic measures, but we call on the MPC to consider carefully the pressures that our businesses are facing and to take calculated steps to bolster economic growth."

Inflation has now been above the Government's two per cent target for four months running. The Bank's governor, Mervyn King has warned that it could rise to more than three per cent, forcing him to write one or more open letters of explanation to Chancellor Alistair Darling.

The biggest single driver last month were prices for petrol and lubricants, which have risen by 19 per cent since January 2006, a rate last exceeded in December 1995.

The cost of goods of all kinds as measured by the long-running retail prices index has risen by 3.3 per cent over the latest 12 months. It was last higher in December 1995.

Food price inflation rose to 6.1 per cent, its highest rate since June 2001.

James Knightley, economist at ING, said the effect of the change in energy inflation calculation "will keep the Bank cautious on inflation".

Howard Archer, UK economist at the consultants Global Insight, said the Bank is likely to be reluctant to cut interest rate further "until it has clear evidence that underlying inflationary pressures are being contained by ongoing wage moderation and by companies' pricing power being diluted by slowing growth".

He added: "Consequently we do not expect the Bank to cut interest rates again until May, unless it becomes clear that growth is slowing substantially."

The RPI, which includes mortgage payments and council tax not counted in the CPI, showed inflation running at 4.1 per cent in January, up from four per cent in December.

The Bank is due to give a further insight into its thinking when it publishes the quarterly Inflation Report this morning.