Small businesses could be in for a rough ride over the next couple of years after a surprise hike in inflation made interest rate rises almost inevitable.

Official figures out last week revealed that inflation had jumped to 3.1%, well ahead of the government’s target of 2.0%, and many analysts are now predicting a rise of at least 0.25% – and possibly 0.5% – when the Bank of England’s monetary policy committee meets next month.

Some commentators have suggested interest rates could reach as high as 6% by the end of the year, which could cripple small companies in loan repayments and dwindling customer and business spending. One group of leading monetarists has even predicted that rates will hit 7.5% in 2008.

In a speech to the Treasury Committee, the governor of the Bank of England Mervyn King pledged to bring about a “sharp decline” in the rate of inflation over the next four to six months, further adding to the likelihood of imminent rate rises. “There could be a sharp fall in inflation in the next four to six months,” he said. “We are completely determined to bring inflation back to target. That’s our purpose in life.”

The Ernst and Young Item Club also warned of tough times ahead in its quarterly report, adding that it was only the strength of the business sector that was protecting the economy from a slowdown.

The organisation’s business advice report claims strong business growth would boost GDP growth to 2.9%, up from 2.8% last year. Business investment at the end of last year was up by 13.5% on the figure at the end of 2005, it added.

“It is really amazing just how strong the business sector is,” said Peter Spencer, the author of the report and chief economic adviser at the Item Club. “It all stems from profitability, which has been going up throughout the world, throughout the recovery. We are looking at a renaissance.”

But the group was less positive about consumer spending, on which many small businesses and business startups depend, claiming many people were overly relaxed about risk and “spending like it was going out of fashion”.

“The bottom line is that we are all living beyond our means,” said Spencer. “Ultimately we are all skating – not to say wobbling – on thin ice.”