Consumer inflation in the UK hit its highest level in nine months but only because of a new way of calculating energy bills, according to the Office for National Statistics.

The Consumer Prices Index reached 2.5% on a year-by-year basis, taking it well above the government's target of 2.0%.

But without the new method for energy bills the figure would have stayed at 2.2%, the ONS said.

The Retail Price Index, which also includes mortgage payments, remained at 4.1% while core inflation - which omits food and fuel - fell to 1.2%, the lowest rate since August 2006.

Concern over rising inflation is the biggest obstacle to the Bank of England being able to boost the economy by lowering interest rates.