Since launching in the UK in summer 2013, EDT Automotive's engine detox treatment has generated over £1.1million in turnover for franchised dealers including Inchcape, Sandicliffe and Hendy Group.

The hand-built EDT machine cleans petrol or diesel engines with an environmentally friendly solution. It takes 15 minutes to remove up to half a litre of thick black sludge (carbon and metallic particles, varnish, even the odd broken-off dipstick) – what doesn’t come out in an ordinary oil change.

The company claims the results to be close to doing a manual engine strip, with fuel economy increased by up to 20%, power increased by up to 6bhp and torque increased by up to 7ft-lb. Harmful emissions are also significantly reduced.

Victor Wood of Grantham general manager, Andy Doyle, said: "The first thing we did was get our technicians to test it on their own cars. They can be quite sceptical about anything new but they all said EDT makes a real difference.

"We are lucky that our workshop is always at maximum capacity, but we were looking for extra profit. EDT does exactly that. You plug it in and leave it. The technician gets on with his work and it earns an extra £40 or £50 per job. The way I see it, EDT pays the mechanic's wages for a couple of hours, so the service is 100% profit for the business."

Managing director at EDT David Holmes AAE FIMI AIRTE said: "We are well on the way to establishing a true nationwide network and the fact we've done that from scratch in under two years tells you everything you need to know about the quality of the product.

“The benefits are such that dealers are now using it to reduce their fleet running costs and in used car preparation."

EDT operates a pay-as-you-go model similar to a vending machine company, providing the unit, sales and technical training, the consumables and ongoing support. The minimum contract requirement is five treatments per week.