The green technology still isn't officially confirmed for right-hand drive markets like the UK, but Mercedes' UK boss says he believes it's only a matter of time.

Bluetec is the umbrella name for a number of technologies that work together to create more efficient diesel engines. The result is higher fuel economy and lower CO2 emissions.

It made its world debut in America 12 months ago in the E-class, where it now accounts for one in five sales of that car. It will appear in the R-Class luxury crossover and ML and GL-Class SUVs in that market soon.

Bluetec E-class will arrive in European showrooms from December, and now Mercedes has revealed the technology will go into the C-class from 2009. Two models will be available, a C250 returning 57.7mpg fuel economy, and a C300 hybrid with 61.4mpg.

Speaking at the launch of the C-class wagon and C63 AMG performance flagship saloon, Mercedes Car Group UK managing director Dermot Kelly said: "The focus has been on the big prize which is converting America, that's why we went into the US first with Bluetec. Europe is a much more diesel-oriented market and to launch it here would have been easy."

"However, Bluetec is still not confirmed for the UK. There's a chance it might not happen, but I don't think that's the case. I believe it's a question of when, not if."