The hydrogen-powered car was competing for the first time alongside petrol engines at a Shell Eco-Marathon Challenge, held at the Grampian Transport Museum in Aberdeen.
Each year, teams from across the world travel to the village to trial vehicles with incredible fuel efficiency. Judges compare how much fuel each vehicle has used on the circuit.
The car was created by Kenny Stewart, a builder of ultra-light eco-marathon cars, and Dave McGrath, managing director of Aberdeen-based siGEN, which markets fuel cells as back-up power supplies. Gas company BOC supported the prototype.
During fuel economy trials, the BOC gH2Ost achieved an equivalent of 1,200mpg, based on the calorific content of the hydrogen it used. It weighs just 100kgs, including driver, and has a top speed of 15mph.
The result was far short of the 10,700mpg record achieved this month by a petrol engine, but McGrath said it was a very good result considering the car did not exist just a few months ago.
McGrath added: 'Looking at the data, we believe that 80% of the fuel losses in the system could be corrected, which means we could achieve up to 9,000mpg.
'We would be happy to work with any company looking to beat the fuel cell economy benchmark we have reached.'
Fuel cells work by converting energy stored in hydrogen atoms directly into electricity. This is achieved by bringing together hydrogen and oxygen in an electro-chemical reaction, which creates water as a waste product. Most major car manufacturers are investing heavily in fuel cell technology, although experts believe it could be up to 20 years before they become a viable transport choice.
The fuel economy world record stands at 10,705 miles per gallon and was achieved by the French Microjoule team with a petrol-driven vehicle at the Rockingham Motor Speedway in Northants last month. This topped the Japanese Fancy Carol team's record of 10,240 miles per gallon, set in 2001.