British workers have shown a French carmaker how to build more reliable models.

After a succession of reliability problems dented the appeal of its Laguna saloon and Sport Tourer range, Renault asked for help from Nissan, its Alliance partner.

Top executives were sent to Sunderland to see what lessons could be learned from the assembly processes in Europe’s most efficient car plant. The result has been sweeping adaptations to operations in all its 35 global production sites.

The greatest impact has been felt at Sandouville, the Normandy centre responsible for Laguna, Espace and Vel Satis. It’s now focused on executive vehicles.

“We have copied many ideas from Nissan. All our operations have been reconfigured, our workstations have been optimised and we’ve worked hard on verification processes,” Renault manufacturing executive vice president Michel Gornet told AM.

“All the quality problems of the previous car are behind us and we are now turning out cars that are compliant and consistent.”

Every Laguna is subjected to full diagnostic checks and a 600-metre test drive to evaluate ride, handling and suspension before being signed off for delivery – measures seen as vital to chairman Carlos Ghosn’s plan to add 800,000 to annual volume by 2009 and turn Renault into Europe’s most profitable carmaker.

The Laguna is set to play a key role by becoming one of the three top cars in its segment for quality and service and the hope is that the new version will revive fortunes in the UK, where Laguna sales of 30,404 in 2002 had slipped to 7,469 in 2006.

D-segment programme director Patrice Ratti said: “After we recover our position with Laguna, we will begin to market luxury cars. From the end of next year, we will launch the Laguna Coupé with the 3.0-litre turbodiesel engine that will also be used by Infiniti, a new Espace and then the replacements for SM5 and SM7, luxury sedans built by Samsung in Korea that could be offered in Europe.

“The effect of this will be to step up our market position by 2011. In terms of quality, I think we are already on a par with the premium German and Japanese brands.”