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Can you cut petrol costs just by driving more smoothly? Patrick Collinson gave it a go and found that a driver doing 15,000 miles a year at an average 119.9p a litre could save a fortune

Video: Patrick Collinson takes to the road

I don't hammer down motorways. I don't break speed limits. I've never been responsible for a car accident, and never had any points on my licence. I think of myself as a cautious, weekend-only driver (I cycle weekdays) who chugs along in a 10-year-old estate car. And like everyone else, I'm horrified that filling up my tank sets me back more than £70. So when BP invited me to spend a day learning how to drive all over again, lose my bad habits and gain some good ones, I was sceptical. Would it really make that much difference to my petrol consumption?

The answer is: yes. My first test run was in a diesel-engined Mini Cooper, and I clocked up what I thought was a respectable 39.6 miles per gallon (mpg). Yet automotive engineer Anthony Sale drove the same Mini round the same track – at Millbrook Proving Ground in Bedfordshire – completed the course faster than me, and achieved an extraordinary 63.3mpg. In other words, I can get 60% better consumption, produce lower emissions and still drive faster. What's the secret?

Millbrook is familiar to viewers of the BBC's Top Gear: a vast high-speed bowl for extreme vehicle testing, a five-lane motorway, hill routes and mock city streets, all security-patrolled as car manufacturers put top-secret models through their paces. And, last week, there was me, pootling around, an Aston Martin often on my tail, and superbikes scorching past.

But back at Millbrook mission control, the computers linked to the Mini's engine told a different story. I wasn't pootling. I was over-revving, driving in too low a gear, accelerating and decelerating too much, and failing to react properly to road conditions.

The computer spat out its conclusion: I am a rubbish driver, I'm wasting vast amounts of money on petrol and destroying the environment. If I drove efficiently, I could save £7,734 over 10 years, and cut 16 tonnes of CO2 emissions. OK, that's if I were driving 15,000 miles a year at an average cost of 119.9p a litre, whereas I drive around 4,000 miles a year, so my savings would be lower. But I can see the point.

So what am I – and millions of other drivers – doing wrong?Over-revving

I never look at the rev counter – but Sale tells me I'm letting the rev count go too high before I change gear. He says I'm not alone – drivers typically let the revs run to 3,000 per minute on a petrol car and 2,500 on a diesel before moving up a gear; Sale says we should be changing up when we hit 2,500 revs on a petrol and 2,000 on a diesel, and move into fifth (and sixth on new models) at the appropriate point. I listen to the engine before moving up gear – so I've got to change my listening habits. And going into too high a gear too soon is also wrong: "Labouring the engine in too high a gear can actually increase fuel consumption," says Sale.Acceleration and deceleration

"Stamping on the brakes and then accelerating hard is efficient driving's worst enemy. An efficient driver is a smooth driver," says Sale. The computer shows that I accelerate too fast out of roundabouts, and decelerate to a halt at junctions. On the motorway stretch, I go up and down between 60mph and 70mph when it is crucial to maintain a steady cruising speed.

By contrast, the graph of Sale's driving shows that on sections of the track he is not using any fuel at all. This is when he's cruising in gear towards a roundabout, letting the car slow by itself. I, on the other hand, occasionally put the car into neutral and let it coast, which is a no-no. "Lifting off the throttle, rather than putting it in neutral, means you will use no fuel at all," says Sale. It's safer, too.Speed bumps

Braking hard, accelerating, then braking hard for the next speed bump means your car will drink petrol, says Sale. He tells m

Tags: Motoring, Saving money, Consumer affairs, Money, Motoring, Technology, Environment, Travel and transport, Carbon emissions, Ethical and green living, The Guardian, Features

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Save £800 a year on petrol was originally published by Technology: Motoring | guardian.co.uk. Read the full story by clicking here.