The Sunderland workforce produced 105 cars per employee last year compared with 76 for its two nearest rivals - General Motor's Eisenach factory in eastern Germany and Volkswagen's Navarra facility in Spain - a productivity gap of 38 per cent.
Another Japanese transplant manufacturer, the Toyota plant in Burnaston, Derbyshire, also moved up, leaping from 12th to 5th place in the league with 72 cars per employee.
However, Rover's Longbridge plant in Birmingham, which spent part of last year under threat of closure, dropped a further six places down the rankings with an output per employee of only 30 cars a year, putting it in 30th position.
The figures, produced by the Economist Intelligence Unit, show that overall productivity at Europe's car plants rose by 11 per cent last year to an average of 52 cars per employee. It attributed the improvement to increased automation and an emphasis on designing cars that are easier to assemble and so require less rectification work.
Nevertheless, the gulf between the best and the worst remains enormous. Sunderland's performance makes it the 10th most productive car plant in the world. Its 105 cars per employee - up from 98 the previous year - compared with a world best of 160 in Japan and 87 at the most efficient car plants in the US.
The EIU sounded a note of caution, saying that Nissan's productivity levels could be threatened this year because the Primera is undergoing a full model change while the new Almera does not go into production until early next year.
Output from Sunderland is expected to drop from just under 289,000 in 1998 to around 280,000 this year. However, it will rise to 350,000 next year - 50,000 more than its design capacity - when the Almera comes on stream. The launch of the new car will increase the workforce from 4,200 to 5,000.
The EIU blamed Longbridge's poor productivity on falling demand exacerbated by plant refurbishment. But it predicted that the pounds 1.4bn investment in new models by Rover's parent company BMW would produce a slow improvement over the next two to three years.
Honda's Swindon plant also crept into the top 10 with output per employee of 64 cars a year. Ford's Dagenham plant was again its most efficient in Europe, even though cars per employee dropped from 62 to 61.
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