Toyota, the Japanese car group, last night issued an apology for comments from a senior executive that its British employees do not work as hard as their French colleagues.

Kosuke Shiramizu, board member for global production, was effectively slapped down for speaking out of turn in claiming that Toyota's Valenciennes plant was 20% more productive than Burnaston, Derbyshire, and Deeside, north Wales. "In France there are many unemployed people and so [those with jobs] tend to work harder," he told the Financial Times in remarks that Toyota in both Japan and the UK labelled as entirely personal and unrepresentative of company policy.

But, even with the apology, union leaders smelled a rat, suggesting that it was unusual in Japanese corporate culture for an executive to speak at all without board clearance in advance. Officials at Amicus, which has a single-union agreement at the plant and 1,600 members, remain suspicious that Toyota was softening up its British "members" for a poor pay offer or even for a shift in production overseas.

Toyota, which produced 211,000 cars at Burnaston last year, offered a further olive branch with news that it is to export the revamped Avensis built at the plant to Japan. Alan Jones, UK managing director, said: "This is the first time a Toyota plant in Europe has begun exports to Japan and recognises our continuing development. We expect to export around 20,000 units annually."

Toyota has invested £1.7bn in Burnaston, opened in late 1992, and the newer Deeside engine plant but admits that both operations have been unprofitable in recent years because of the pound's strength.

Burnaston, which plans to produce 220,000 Avensis and Corolla models this year, exports 80% of its output to Europe where, apart from France, Toyota is building plants in Poland the Czech Republic.

The Derbyshire plant is rated the joint second most productive in Europe, after Nissan's Sunderland factory, and produces 87 vehicles per employee per year. Valenciennes, opened in early 2001, has not yet been included in the same survey.

French productivity is overall at least 20% higher than that of Britain but Toyota said exact comparisons between its plants could not be made because the UK produces two models with five variants and the French one just the Yaris.

The Valenciennes factory, the first Japanese "implant" in France and hailed in a depressed northern region, cost £400m, employs 2,500 and churns out 180,000 units a year.