Last month saw Glass’s predict that bigger, less efficient engine cars could make a return in both the new and used markets as pump prices reach their lowest level since 2009 and consumer confidence grows.

Yet CAP has said that high road tax for less efficient engines continues to outweigh any possible savings in fuel, despite pump prices falling to a five-year low.

For example, a family tempted to switch out of a 2.0-litre Vauxhall Insignia 16V Elite 5dr Auto and into a V6 version Vauxhall insignia 2.8T 4×4 Elite 5dr Auto this year would find themselves paying £215 more just for their road tax. 

Meanwhile the V6 Insignia would cost around £300 more for fuel over 10,000 miles – even at today’s lower pump prices – compared with their previous car. And this week has already seen the Petrol Retailers' Association warn that fuel prices are up their way up again.

CAP adds that when you throw into the running costs mix typically higher insurance, service, maintenance and repair bills and motorists could pay a heavy price for being tempted to reconsider such cars. 

And it also brands the assumption that drivers naturally desire larger-engined and less economical cars, if only they could afford to run them, as “1970s thinking”.

CAP’s retail & consumer expert Philip Nothard said: ‘We know from the intelligent consumers who research car costs on our website that the typical car buyer in modern Britain has long moved on from the old days of simply wanting the biggest, most powerful engine they can have. 

‘The assumption that lower fuel prices will unlock pent-up demand for a return to some kind of golden age of gas guzzlers is thinking that belongs in the 1970s.

‘We have also been extensively researching this issue among motor dealers and they confirm to us that fuel economy has not slipped at all down the list of priorities for the typical customer.

‘Doubtless the odd “petrol head” with a thirsty classic in the garage will be tempted to do a bit more driving while fuel is cheaper, but the suggestion that we are on the brink of a resurgence for less efficient cars is simply a schoolboy error.’