Food prices in the big four rose sharply this month, fuelled by the combination of VAT returning to 17.5% and the end of Christmas promotions, data from The Grocer Price Index reveals.

The average shopping basket cost a hefty 2.8% more in January than the month before, the biggest monthly increase for two years, and a worrying sign for retailers enduring an anaemic economic recovery. Year-on-year food inflation also jumped sharply, up from 1.6% the lowest value in two years to 2.6%, marking an end to near-zero inflation in late 2009.

The rise suggests that when the UK's official inflation figures are published in mid-February, Bank of England Governor Mervyn King will have to write to the Chancellor explaining why inflation is over-target.

Alcoholic drinks showed the sharpest rise last month, jumping 7.5%, hit by the double whammy of VAT increases and the end of Christmas promotions.

Fruit and vegetables was one of few categories to fall in price last month, 2.4% cheaper than before Christmas.