Almost every Mercedes-Benz diesel car bought in the UK since 2011 is to be recalled over concerns over toxic emissions.
Parent company Daimler has announced the cars will be fitted with new software to reduce emissions output as part of a voluntary recall.
Customers won't have to pay anything for the work, but Daimler has yet to say whether it is considering paying any compensation.
Yesterday the Daimler board of management announced it was recalling one million Mercedes in Germany, and two million from elsewhere in Europe. It has declined to say how many UK customers are affected, but 170,000 new Mercedes-Benz cars were registered in the UK last year alone.
The recall is for the majority of its cars that are listed as meeting the Euro 5 standard, which was brought in on 1 January 2011, or the later Euro 6 standard which came into effect on 1 September 2015.
It's expected to cost the company €220 million.
The work is expected to start within a few weeks and we've asked Daimler what customers should do if they have any concerns in the meantime.
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Dr Dieter Zetsche, chairman of the board of management of Daimler, said: "The public debate about diesel engines is creating uncertainty - especially for our customers.
"We have therefore decided on additional measures to reassure drivers of diesel cars and to strengthen confidence in diesel technology.
"We are convinced that diesel engines will continue to be a fixed element of the drive-system mix, not least due to their low CO2 emissions."
Daimler said in May that German investigators had searched its offices in connection with investigations of Daimler employees because of suspicion of fraud and criminal advertising relating to the possible manipulation of exhaust controls in cars with diesel engines. The company has said it is co-operating with the investigation.
There has been increasing scrutiny on emissions, with VW recalling 1.2 million cars in the UK last year. See our MSE VW emissions scandal: what does it mean for you? News story for more information.Additional reporting by the Press Association.