Drivers face paying more than £1.10 a litre for fuel after petrol and diesel prices increased by another 2p in the last month, the AA said today.
It follows a 4p hike between March and April, and leaves the £1 a litre fuel of earlier this year firmly behind.
The motoring group said surging oil prices, which are heading towards $50 a barrel, threatened further increases.
Petrol averaged 109.2p a litre across the UK and 108.9p in Scotland on Monday, according to its monthly fuel price report.
Diesel averaged 109.1p and 0.1p less in Scotland.
However, the AA said these levels were 6.5p-11p cheaper than a year ago.
Cheapest prices in Edinburgh and Glasgow for both fuels were 104.7-105.7p, comparison site petrolprices.com reported.