Car repair bills across Great Britain differ wildly, according to a new report by Auto Express in association with Warrantywise.

The survey found that one garage in Surrey charged £240 an hour for car repair work, contrasting starkly with a garage in Birmingham which charged just £36 an hour.

And while London rates were generally high, there were instances of exceedingly high charges outside the capital.

In one instance a garage in the Scottish Borders charged £91 an hour, more than in north London, where the hourly rate averaged £81.

Graham Hope, the deputy editor of Auto Express, said: "Obviously, higher hourly rates in London are to be expected, but the huge difference in average costs across Great Britain shows motorists are not being treated fairly.

"And a difference of £204 per hour between individual garages is completely unjustifiable."

UK-wide the average cost was £84.30 per hour.

London averaged £101.60 – the most expensive location, while in Scotland it was £71.42 – the cheapest place to have a car repaired.

Lawrence Whittaker, Warrantywise's chief executive, said: "Some of the differences Warrantywise has discovered are, frankly, offensive.

"Our advice is simple: shop around, negotiate and remember that as a paying customer, you are holding the ace cards."

The findings of the survey were based on calls made to 1,200 garages across England, Scotland and Wales.

As of 2011, Auto Express was the best-selling automotive magazine in Britain, with a circulation of 60,840.

Warrantywise, which conducted the survey with Auto Express, provides warranty services to dealer groups across the UK.