Petrol prices may be at their highest level ever, but BP is gambling that a niche group of drivers will still be willing to pay more than twice as much.

The oil company has launched the highest octane fuel available on forecourts in Britain, aimed at drivers of high-performance cars. It costs £2.42 a litre — £11 a gallon.

Ultimate 102 has an octane rating of 102 RON, compared with 95 RON for standard unleaded petrol and 99 RON for the highest-rated super-unleaded. It is similar to the old five star petrol sold in the 1970s which cost only a few pence more than regular fuel.

BP’s target is the growing number of owners of top-end sports cars who want a little more power and performance from their tuned engines, especially on track days. The company claims it can add as much as 37bhp to a turbocharged vehicle.

The fuel, which is “crystal clear” rather than the yellowish colour of regular petrol, is so exclusive it is “hand made” in small batches using the sort of expertise employed by Formula One race teams, says BP.

But is anyone really going to spend £100 on one tank of petrol? Ultimate 102 went on sale on six forecourts in southeast England last Monday. The Sunday Times monitored two stations for 48 hours last week and witnessed only one purchase. Calls to the other garages revealed just five confirmed sales (three refused to comment). BP says all six stations have made at least one sale. Pressed on exactly what quantity had been sold, a spokesman said the response had been “ overwhelming”.

Overwhelmingly bad, perhaps. Even BP’s own station managers were sceptical. Ade Layokun at the Tudor filling station on the A20 in Maidstone said: “Even for the high-end road user it’s too expensive. People pick up the pump then quickly drop it.”

At the Newbury Centre filling station in Ilford, Essex, drivers were required to push a large orange button on the pump to signal their acceptance of the price. When one elderly lady inserted the nozzle of the superpetrol in her Fiat Punto the cashier warned her over the intercom and she beat a retreat.

The other buyers according to staff were the driver of a Subaru Impreza and a customer who filled a 5 litre can. The only purchase witnessed by The Sunday Times was at the Canning Town station, east London, by Jermain Shillingford, a 24-year-old courier. He put £15 worth into his Renault Clio Williams. That bought him 6.2 litres.

Shillingford said he had spent £7,000 souping up his 13-year-old car with gold hubcaps, a stainless steel manifold and a straight-through exhaust. He planned to begin racing his car and hoped the fuel might give him an edge.

“I thought I’d give this a try. I know turbo cars will get more performance out of it. This is a normally aspirated engine — it might gain a little bit, might be a little more responsive. I won’t be buying it all the time, though.”

The biggest customers for the new petrol were Kent police who made two purchases last week, filling up their Volvo patrol cars using the taxpayer funded police fuel account at the Tudor filling station.

After being contacted by The Sunday Times, Kent police warned staff against using the fuel again, saying it was an “error”. Jon Parker, a spokesman, said 95 or 97 octane petrol was adequate for the police force’s vehicles.

BP claims to have extensively tested the new petrol on a range of high performance cars, including a Porsche.

Andrew Davis of Porsche says the fuel will not increase power in a Porsche, though it may fractionally reduce fuel consumption and burn more cleanly. “Our engines have a maximum power output. If you put different fuel in, the engine management system won’t allow the engine to produce more power. All our cars will run on standard 95 RON unleaded, although we advise 98 RON for some of the turbocharged cars.”

Chris Walsh, technical manager of the Society of Motor Manufacturers and Traders, says the fuel would be of little benefit to most motorists. He said he would be surprised if there were a perceptible improvement in the performance of Shillingford’s Clio Williams.

“Clearly fuel price is a sensitive issue, but some people have got quite a lot of money to spend. I can see that if people were going to a track day they might use it to get half a second off a lap.”

BP, which last week unveiled profits of £2.95 billion for the first three months of 2006, stands by its expensive new product. “Performance benefits should be noticeable immediately for those with performance cars,” says Nicola Beckett, UK marketing manager for BP Ultimate.

She says trials have shown improved performance on cars including the Mitsubishi Evo, Ford Focus ST and Subaru Impreza, once they were tuned for the fuel. “For someone who does have a car which they’ve spent a lot of time and money on, we think they will pay the price. This isn’t aimed at the average driver — the price to them will seem astronomical.”

The fuel will be available from nine sites this year. BP will then assess whether there is a wider demand.