Fleets adopting greener vehicles to cut their carbon emissions and reduce operating costs have been warned that hybrid vehicles could cost significantly more to repair then their petrol and diesel counterparts.

According to research carried out in the US, the Toyota Prius cost 8.4% more to repair than its petrol-powered counterparts, while hybrid vehicles in general averaged almost 4% more to repair.

However the findings have been refuted by Honda, which makes the new Insight hybrid.

The Insight costs no more to insure – it is group six – than equivalent C sector cars and, according to Honda tests, no more parts are damaged nor need replacing and there is no additional cost following a like-for-like crash.

Audatex Directions, which carried out the research, blamed design changes made by manufacturers to reduce hybrid vehicle weight or better accommodate the hybrid system on the increased repair costs.

“These subtle design differences can result in higher part prices, repair costs and limited alternative-part availability,” said Audatex.

However, Honda points out that it is these very changes – such as reducing the size and weight of the battery and placing it below the rear seats in the Insight - that help keep costs down.

The US findings will impact fleets here, as engineers from Thatcham, the UK motor insurance repair research centre, explained.

“The situation in North America with increases in repair cost is primarily due to the proliferation of hybrid vehicles in the US and it is certainly something that the UK will be facing in the coming years, as hybrid vehicles become more commonplace and crucially the battery size and technology advances and becomes more expensive,” said Andrew Marsh, advanced data and methods manager at Thatcham.

“Indeed it is the replacement of the battery that currently accounts for most of the additional repair cost.

"This will only increase as lithium-ion batteries become more commonplace and more expensive as manufacturers look to get more performance from the battery.”

Mr Marsh said that in the event of a crash, if there is any sign of damage to the battery casing or cooling ducts the battery will normally be replaced, with the valuable materials from the old battery being recycled.