Repsol, the leading Spanish oil company which commands 45 per cent of the market, has increased the price of petrol by two pesetas a litre and diesel oil by five pesetas. The new prices came into force in petrol stations all over the country at midnight. Lead-free 95 octane petrol now costs 140.90 pesetas a litre. The lead-free superplus' 98 octane petrol is 155.90 pesetas, while super' is 151.90 pesetas a litre. Diesel oil has gone up to 124.90 pesetas a litre. Sources at Repsol said that the increase was due to the evolution of the price of crude oil on the international markets and the strength of the dollar, the currency in which oil bills are paid. The three most used fuels in Spain have gone up by an average of 15.49 per cent so far this year. Consumers wasted no time in slamming the increase as inacceptable, and consumer watchdogs repeated their request for the government to investigate the possibility of price fixing by the leading Spanish oil companies. Repsol's increase was the second this week. Cepsa increased the price of diesel oil by two pesetas to 121.90 pesetas, although it is still lower than the new price set by Repsol. It is feared that Cepsa and BP will introduce further increases over the next few days. Repsol had maintained its prices unchanged since August, but the latest increase is the biggest in the company's history. And it is the first time it has applied such a savage increase in diesel oil for reasons other than an increase in special taxes. Company sources justified the increase saying that in the last week alone, the international price of diesel oil has gone up by 6.2 pesetas a litre and the price of a barrel of oil is $35. Spanish Premier José Maria Aznar spoke about the price of oil at the end of the Biarritz summit yesterday and repeated his initiative to lower the tax on fuel, while at the same time criticised the European Union's incapacity to maintain a common front on the matter. But economists have painted a gloomy picture, indicating that this may not be the last increase of the year, as oil prices may go up again if the conflict in the Middle East continues. José María Múgica, the spokesman for the Organisation of Consumers and Users, said that the other petrol companies will follow the leader and increase their prices over the next two or three days.