The price increase follows a long period of stability in fuel prices, which for more than four months – from August to December last year – varied by less than one penny per litre from week to week.
Fleet and fuel management company Arval PHH, which operates the AllStar fuel card, produced the report. It found prices of 76.79 pence per litre (ppl) for unleaded and 78.34 ppl for diesel for the week ending January 23.
It reports that the recent rise in oil prices, with Brent crude now trading in excess of $30 per barrel, is starting to be felt on the forecourts.
Louise Dickinson, managing director of Arval PHH's major customer division, said: 'To observers of the international oil markets, this increase won't be a huge surprise. Crude oil is around its highest price for 10 months and it was all but inevitable that this would feed through into the fuel prices paid by British motorists.
'Although private drivers are feeling the pinch, the UK business community also suffers from higher petrol and diesel costs, especially as fuel counts for about a third of the running costs of a company car.
'The increase in diesel prices, which have now breached the 78ppl level, will hit companies especially hard. Many company car drivers have moved into diesel models because of the CO2 emissions-based structure of company car tax.'
Dickinson added: 'Businesses clearly need to manage their own fuel usage to retain their competitive edge.'
Arval PHH's figures show that in December the average price of unleaded petrol was 76.37ppl.
The cheapest was found in Neston, Cheshire, at an average price of 71.50ppl, while the most expensive was the Isle of Lewis at an average price of 84.90ppl.