The 26-year-old Newtown man converted his 2000 Vauxhall Vectra 2.0D to run largely on vegetable oil 12 months ago.

"I now pay just 87 pence per litre for the vegetable oil as opposed to £1.33 for diesel," he said. "The whole conversion cost me less than £200!"

Faced with a 66-mile a day round commute between his Newtown home and his job in Shrewsbury, Tim was inspired to get radical after he started researching into bio-diesel.

"I found out that you can run older vehicles on straight vegetable oil so I started adding small amounts of vegetable oil to my diesel fuel – at one time I was running the car on 30 per cent vegetable oil to diesel without any conversion," said Tim.

"After more research I stumbled across a pre-heater, which heats the vegetable oil to between 70 to 90 degrees. This allows vegetable oil to flow more smoothly into the engine and you can run the fuel mix at a higher per cent. Using this heater I can now run my car at 90 per cent vegetable oil in the summer months.

"It's nice going to the garage, adding two litres of diesel to the car then popping home and putting in 20 litres of vegetable oil!"

Tim's savings have also increased since a new law was passed on June 30, 2007, stating that you can now use up to 2,500 litres of vegetable oil a year without paying any duty on it.

"I am never going to work my way through that much fuel in a year so it allows me to make monster savings!"

Two of the questions Tim is most often faced with when people hear about his conversion are: Is there any difference in performance levels and does the car smell like a chip van?

"Only a few weeks ago I drove to York and back on 'Crisp n Dry' and the car ran a sweet as a nut," joked Tim. "Seriously, the difference in performance is extremely minimal.

"People always presume it will smell like a chip van but it doesn't. If you stand outside the car there is a nice smell, a bit like popcorn, but you cannot smell this when you are travelling."

And it's not just the £20 a tank saving on fuel and the excellent performance that has delighted Tim, because due to vegetable oil and fat not being mineral-based fuels, the emissions are less harmful.

"It's amazing. By running your car on vegetable oil you not only save money but you also reduce your carbon footprint!"

n Before Tim converted his car he did endless amounts of research – he recommends you do the same before you pour vegetable oil into your car.