Factory gate prices jumped last month as the Treasury’s latest hike in fuel duty came into force, official figures showed today.

Output prices rose 0.5% between August and September pushed up by higher petrol prices, the Office for National Statistics (ONS) said.

The Chancellor’s latest 2p rise – which came into force at the beginning of the month – added an estimated 0.2% to the output price index, the ONS added.

The month-on-month rise pushed the annual rate of increase in factory gate prices to 0.4% – the highest since April after four months of prices declining year-on-year.

Today’s figure is higher than expected by most economists and comes as the impact of the steady rise in oil prices in the months leading up to July 2008’s record begins to drop out of this year’s figures for comparison purposes.

Crude prices declined steeply in the second half of last year, so relatively unchanged prices or a shallower fall this time around creates an inflationary effect in the figures.

IHS Global Insight economist Howard Archer said the the figures were “yet another example of inflation recently being firmer than expected”.

He added “It suggests that manufacturers may have been trying to take advantage of the recent overall stabilisation in output to try to improve their margins.

“However, it seems likely that manufacturers will have to limit their prices over the coming months.”

The Bank of England has slashed interest rates to a record low of 0.5% and made unprecedented efforts to boost the money supply through quantitative easing amid worries of a Japan-style deflationary slump.

But inflation has not fallen as far as expected, mainly due to the diminishing prospects of lower gas and electricity prices this year and a weaker pound.

More official figures today showed the UK’s trade gap in goods with the rest of the world shrinking from £6.4bn to £6.2bn in August – the smallest deficit in three years.

“The tentative global recovery may finally be allowing UK exporters to make the most of the previous drop in the pound,” Capital Economics’ Vicky Redwood said.