The major oil companies have dismissed claims that their ’superfuels’ are not worth the extra money. Their comments follow an article in What Car? magazine which said independent tests found that high-octane premium fuels including BP Ultimate,

Shell V-Power, Esso Supreme and Total Excellium "performed little or no better than their cheaper equivalents", despite the fact that they cost around 7% more per litre.

What Car? said the top-performing fuel in its test was Sainsbury’s 97-octane, which delivered 0.5mpg more than its 95-octane fuel, delivering six miles more per tank.

However BP, Esso and Total all defended their fuels with Total so confident in its Excellium fuel that it offers customers a guarantee. If drivers do not see an improvement in fuel economy Total will refund the difference in price between the cost of its standard fuel and Excellium. Its tests have found that Excellium can deliver up to 30 miles extra per tankful, but with an average of 14 miles.

Meanwhile BP Ultimate promises "up to 28 more miles per tank" but an average of 13 miles.

Shell said that since the launch of V-Power last year, anecdotal evidence suggested that customers had experienced "additional fuel efficiency benefits". It added that V-Power it is its most technically-advanced performance petrol ever marketed in the UK.

Esso added that comparing the performance and economy of petrol was a "complex process" because there were many factors that could affect the results.