The average price of unleaded petrol across the country rose above 115p yesterday, reaching 115.15p, according to data from Experian Catalist.
Although many pumps will already have been selling fuel at that level or higher for several days, this is the first time in over a year the overall average has nudged above the threshold. The price of diesel rose to 116.88p.
The push has been driven by the weak pound to dollar exchange rate and a rise in oil prices that pushed the physical price of the black stuff above $50 a barrel for four days at the beginning of the month.
Oil prices lifted after Opec (the Organisation of the Petroleum Exporting Countries), a consortium of the world's biggest oil producing countries, provisionally agreed to curb oil output by around 700,000 barrels a day at the end of September.
The agreement, which is due to be finalised at a meeting in Vienna next month, would set daily production to between 32.5m and 33.0m barrels a day.
UK petrol prices slipped below 115p last August, in what motorists hoped would be a respite from sky-high fuel costs.