Reports from RAC Fuel Watch showed that the average cost of petrol and diesel on UK forecourts rose in August, despite the cuts made at the beginning of the month. A litre of unleaded was sold for an average of 111.5p at the end of the month, an increase of 0.33p on prices earlier this month. The average cost of diesel, meanwhile, increased by 0.77p. This brought it close to the 2016 high of 112.81p. Though these increases weren't too substantial, the effects of them cancelled out the July fall in average prices of both fuels. Supermarkets reduced the cost of a litre at the beginning of August following on from a request by the RAC. This helped to force down forecourt costs, but since then they have begun to increase again. Increases in cost were triggered by the rise in the cost of oil, which went up by 6 dollars (a 15 per cent increase) during August. Oil prices are currently the biggest variable impacting petrol forecourt costs. The typical cost of filling up a 55-litre family car currently stands at £61.33 for unleaded, and £62.5 for diesel. Simon Williams, RAC fuel spokesman, said: 'There was a strong case for a 3p per litre cut in the price of petrol and diesel in late July, and it was a relief to see retailers going some way towards passing on savings to motorists at the start of August. Since this point however, the oil price has rebounded slightly which has had the effect of pushing up wholesale fuel prices again. 'Motorists have benefited from some slightly cheaper fuel prices in August compared to July, which will have come at a helpful time given the school holidays. 'It is still the case however that the average price of unleaded petrol grew at its slowest rate in more than a year in August, and we are thankfully still a little way off the sorts of average prices we saw earlier in 2015 when petrol hit 117p per litre and diesel nearly 121p per litre.î In terms of regional increases, the north of England saw the biggest changes in cost, with a litre of petrol increasing from 0.57p to 111.18p. Northern Ireland was the only area that recorded a fall, with costs decreasing by 5p.