Values of used ‘Chelsea tractors’ could drop by up to 10% in the next six months as fuel prices continue to soar.

E-retailer, Carsite.co.uk, is warning of another round of price falls for thirsty second hand 4x4s as petrol prices head toward a record 120p per litre – spurred by a weak pound and the Budget’s 3p fuel duty rise.

The last downturn, during the fuel price surge in 2008, stripped thousands in value from used off-roaders and large family cars with many owners unable to sell their vehicle on.

Carsite.co.uk suggests the additional financial burden placed on drivers by the fuel price spike could trigger another drop in buyer confidence for large petrol-powered cars,stripping as much as 10% of value from the least economical used models.

Between early February and March the AA reported a 17% surge in the wholesale price of petrol and a weaker pound continues to put upward pressure on fuel costs.

Alistair Jeff, Sales Director at Carsite.co.uk, commented, 'With record fuel prices potentially sustaining at these high levels we could see a repeat of the knee-jerk reaction experienced in 2008 that saw dwindling values in the large family car market. Whilst the proposed showroom tax will make buying large 4x4s even more expensive, those who have recently invested in a new gas guzzler could be about to suffer from increased depreciation with their vehicle.'

In the wake of high fuel prices in May 2008, the Society of Motor Manufacturers & Traders revealed 4x4 sales dropped almost 20% compared with the same month in 2007.

In July 2008, the price of petrol reached an all-time high of 119.7p per litre propelling a rapid downturn in demand for uneconomical vehicles. As values of 'gas guzzlers' plummeted, dealerships compounded the problem by refusing to take the biggest fuel burners in part exchange, as the models were seen as too difficult to sell.

Second hand 4x4 models that quickly lost value in the 2008 price falls – and stand to fall again in the current market – include the Range Rover Sport, Audi Q7 and BMW X5. As seen in the table below, almost £6,000 – or around 10% – was wiped from the CAP trade value of both the Range Rover Sport and BMW X5 in just six months.

A controversial new showroom tax to be introduced on April 1st, which adds £515 to the first year’s VED for cars emitting 255+g/km of CO2, will make the 4x4 market even more prohibitive to enter.

Since the last fuel price surge, many manufacturers have placed an emphasis on improving the fuel economy of their larger cars with new models coming to market featuring fuel-saving Hybrid or Stop & Start technology.

However the 4x4s and large family cars of the current second hand marketplace, populated mainly by three to six year old cars, are those most likely to suffer against rising fuel prices.