The Birmingham-built Jaguar XJ has overtaken the Lexus LS 430 as the top-rated luxury car in an influential American survey.

The findings, by automotive consulting firm Auto Pacific, was good news for the carmaker which suffered lower sales than MG Rover in August.

Auto Pacific's VSA (Vehicle Satisfaction Award) study is an industry benchmark for objectively measuring owner satisfaction with their new vehicles. The 2005 ratings reflect input from buyers and lessees of new vehicles acquired from September 2004 to January 2005.

Meanwhile Shanghai Automotive Industry Corporation yesterday denied reports it had linked up with Nanjing Automobile to jointly produce Rover cars.

A Chinese newspaper had claimed Nanjing, which bought Rover for £53 million, will produce Rover 25 cars and engines as well as provide engines for SAIC, which will in turn produce the higher-end Rover 75.

It said Nanjing Auto plans to complete the shipment of manufacturing equipment from MG Rover's powertrain operation in Birmingham to China prior to February 2006 and finish installing the equipment in May next year, with production to begin in August 2006.

The newspaper did not provide SAIC's overall manufacturing plan but said the Shanghai-based firm is willing to use the Rover brand name.

"SAIC is more likely to use the Rover brand, especially for high-end cars," an unnamed source close to SAIC was quoted by the newspaper as saying.

But a spokesman for SAIC said: "We are not aware of any deal like this at all. There are is currently no intention to collaborate with Nanjing."