No driver enjoys a fuel crisis, least of all those of us who cover big mileage or have lengthy commutes. The extra pennies per litre add up and bite hard.

That's true even if, like me, you drive one of the most economical cars on the market. So I thought it a particularly prudent time to see just how economical Toyota Prius that I've been running can be in everyday use.

I start on a fuel station forecourt, where I brim the Prius's 40-litre tank from near-empty and it costs me just over £60. (Last month it was £45.) For that you get 467 miles, the car tells me. Remember that number, because it will be important later.

Next, I head to the public chargers and top up the plug-in hybrid's 13.6kWh battery for around £7 (at 48p per kWh), which nets me 35-40 miles of real-world range. Of course, it would be much cheaper to charge at home, via a three-pin domestic socket or a 7kW wallbox.

The plan now is to drive until the car's two energy sources are drained. I have a few journeys to do over the coming days, starting with a commute to work (roughly a 140-mile round trip), a drive to Gatwick airport (200 miles or so) and then on to Hereford (around 260 miles).

But this won't be a sitting-behind-a-lorry, uber-MPG test like Matt Prior recently did in his Audi A2. Instead, I'm not going to change my driving style at all and the only thing I've really done to prepare is to pump up the tyres. If things go as expected, I'll need to fill up on my way to Hereford.

Another strand to this test is to discover what the Prius is like on a long journey. I've only had the car for a few weeks so this will be the most I've driven it to date, and on the widest variety of roads.

I don't have to wait long before I start finding out. Early on in the test, as I approach Four Marks on the A31, I begin to feel what Toyota has tweaked as part of its efforts to reposition the saloon from a taxi rank regular to a PCP shortlister: there's a whiff of potency.

Previously, the car's 2.0-litre petrol four and electric motor have paired together in a polite, no-frills way, working well especially at motorway cruising speeds. But as I hit some winding dual carriageways, I remember that they combine for 223bhp and a 0-62mph time of 6.8sec, which is quite sprightly. So I put my foot down – and it's quite a laugh, especially with that small steering wheel and low-set seat. Suddenly, I recall chief sub-editor Kris Culmer's short review when he handed back the keys after a go recently: "A Prius shouldn't feel that quick."

Given the way I'm driving the car, this test seems bound for an early end – and I'm on the M4 near Swindon when the 'you have 30 miles left' alert message appears. However, any doubters can hold their sniggering because this is on my way back from Hereford, some 500 miles since I filled up. I'm actually quite staggered. The on-board computer reads 62.4mpg and reveals that 39% of my total mileage since refilling has been done on electric power. I ran out of external charge 460 miles ago, so this has been via brake and engine regen, which is mightily impressive.

In total, it has cost 13p per mile, which is a revelation during a period of heavily inflated pump prices. And that number would have been even less if I'd charged the Prius via a cheaper home dock.

On the surface, the Prius might seem like a dull thing – a viewpoint many have been eager to share with me – and there are more exciting rivals (the Volkswagen Golf GTE and Honda Prelude to name two). But the Toyota's aero-centric design and clever underpinnings deliver something that honestly boggles the mind. I'm starting to really admire this car. It's an impressive machine.