Jon Harris doesn't dither between four star or unleaded. He goes straight for fish and chip oil every time.
The councillor finds his Citroen ZX goes farther on the recycled chip shop leftovers and is much cheaper.
While rising petrol prices are forcing many back to public transport, Coun Harris, 38, is testing out new fuels in his role as lead environment councillor on Eastbourne Borough Council.
The father-of-two hopes the idea of pootling along with cod and haddock fumes belching from exhausts will catch on.
He said: "It smelt slightly different than normal diesel but overall, the car worked fine. There was certainly nothing fishy about it."
The oil costs 32p per litre compared to 73p for diesel.
Coun Harris, of Astaire Avenue, Eastbourne, has asked council officers to look into using cooking oil in their vehicles.
John Stubbs, of the Automobile Association, said: "Modern diesel engines need very refined diesel fuel. You cannot expect to put any old fuel in".
Cooking oil sales have soared in parts of west Wales as thrifty motorists attempt to evade fuel tax.
Police have warned motorists they are breaking the law as all cars on public roads must pay fuel tax.
Some motorists have been fined up to £500. The maximum penalty for fuel tax evasion is seven years in jail.
Mr Harris, however, is using a legal bio-diesel fuel manufactured by a Kent-based manufacturer who neutralises and filters the cooking oil to make it fit for car use.
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