The average price of a litre of unleaded petrol has exceeded £1 for the first time in more than seven months.
The average price is now 100.12p, its highest level since October 2008. The average price for a litre of diesel has increased to 103.85p.
Prices for both unleaded and diesel have been increasing throughout 2009. In January, the average price per litre of unleaded was 85.89p, with diesel at 98.06p.
The increase in cost at the pump has been blamed on rising oil prices and an increase in fuel duty.
Prices for crude oil hit a seven-month high earlier this week, with US light, sweet crude costing $68.58 (£39.96) a barrel, compared with $34 (£20.72) a barrel in February.
A further 2.1p was added to a litre of fuel when the Government's fuel tax increase came into force on 1 April.
Motorists will be hit again in September, when fuel duty is set to rise by a further 2p per litre.