An online service by the Consumer Council telling drivers where to buy the cheapest petrol has been given the thumbs down. Critics said the watchdog had failed to consider the needs of motorists, who would not switch oil companies just because of lower prices. The website - Consumer.org.hk/pricewatch/oilwatch/ - was launched yesterday. It showed Sinopec offered the cheapest petrol, while Caltex had the cheapest diesel. Drivers can also enter their preferences, such as which credit card will be used and bonus schemes, and the lowest price will be worked out. The council's chief executive, Connie Lau Yin-hing, said: 'The calculator is designed to help motorists navigate through the myriad credit-card rebates and bonus-award loyalty programmes which oil companies offer from time to time.' She said a mobile-phone edition would be launched later. The council hopes the service will force oil companies to lower their prices when cost-conscious drivers switch to cheaper retailers. Wesley Wan Wai-hei, president of the Hong Kong Automobile Association, however, said convenience was often more important than price. 'A driver tends to stick to one oil company, sometimes because it has more pumping stations, and sometimes because he has joined the company's loyalty programme,' said Mr Wan. 'The price difference is not very big. You won't drive 20km for cheaper fuel. And few drivers would bother to switch oil companies every week just because they can save a few dollars each time.' Stanley Chaing, a convenor of the Fuel Price Concerning Transportation Joint Conference, described the service as 'a cosmetic gesture'. 'The council only wants to show it is doing something. It would be silly for them to think a new webpage can bring prices down. The oil companies keep charging high prices because there is not enough competition,' said Mr Chaing. Democratic Party legislator Fred Li Wah-ming also criticised the council for failing to address the core issue of fuel prices failing to keep pace with falling oil prices.