Factory gate inflation rose faster than expected in December to its highest annual rate since April, driven by a sharp rise in the price of crude oil and food input costs, official data showed last Friday. The news is likely to concern the Bank of England as consumer price inflation is already more than a percentage point above its 2% target and is forecast to rise towards 4% in the coming months. The Office for National Statistics said producer output prices rose 4.2% in December, slightly above forecasts for an annual rise of 3.9%. On the month, output prices were up 0.5%, versus a 0.4% forecast. December input prices were 12.5% higher on the year, also the highest annual rate since April, compared with a 9.2% annual rise in November and against forecasts for an annual rate of 10.4%. Economists had expected some acceleration in input costs due to higher oil and gas prices and the weaker pound. A slowdown in the growth of labour costs had been expected to keep output prices steady. Stripping out input costs for food and petroleum industries, the annual rate of input price inflation in December rose to 8.8% from 7.5% on a seasonally adjusted basis