It comes after July saw a second consecutive month of average fuel price rises as retailers 'wasted no time in passing on wholesale price increases' following a huge jump in the cost of oil.
Over the weekend, the average price of diesel rose above 150p-a-litre for the first time since May, while petrol reached a six-month high.
The AA reports that diesel reached an average of 150.61p on Sunday, having last been above that level on 21 May (150.80p).
In between, it had fallen as low as 144.31p on 18 July.
Petrol rose to 149.13p-a-litre at the weekend, an average last seen on 4 February (149.17p). Its low-point was 143.04p on 7 June.
'A 5p-a-litre increase in just over a fortnight will lump pressure back on diesel users, particularly on small businesses, and results directly from the oil price hike that was brought on by production cuts,' explains Luke Bosdet, the AA's spokesman on road fuel prices.
'By the end of last week, the wholesale price of diesel was 11p a litre higher than in mid-July.
'Whether that continues or turns round before finding its way to the pump will be critical for UK inflation.'
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