Sales of petrol at the pumps have dipped sharply over recent years, according to Government figures highlighted today by the AA.
In terms of weight, petrol sales fell 13.95% between 2007 and 2010.
Sales totalled more than 16.80 million tonnes in 2007 but by last year this figure had fallen to just over 14.46 million tonnes.
Diesel sales rose - going up 6.85% from 12.34 million tonnes in 2007 to 13.19 million tonnes in 2010.
The 2007/10 fall in petrol sales is the equivalent of 3.19 billion litres - equal to 52 days of petrol consumption in the UK.
AA president Edmund King said: "On the face of it, it looks like the UK driver is hitting back against record petrol prices by buying considerably less of it, perhaps by buying more fuel-efficient cars, adapting the way they drive and rationalising their journeys.
"Unfortunately, the reality is that many poorer motorists can't afford to pay for petrol and are increasingly leaving their cars idle."
He went on: "The drop in fuel sales puts a squeeze on retailers and fuel suppliers, who face the dilemma that increasing prices to compensate for lower sales volumes simply pushes more drivers into road fuel poverty.
"The Government's freeze on fuel duty last week will have prevented many drivers being tipped over the edge, but the AA suspects that there will be little improvement on the forecourts come the 3.02p-a-litre duty rise in January."