Fewer than 8,000 of BMW's 100,000 workers bought a BMW last year and, with sales down around 14% in the first five months of the year, asking your own workers to buy the cars they design, build and sell makes sense.

So BMW targeted its workers' car parks, putting 7,000 postcards on assorted Audis, Mercs, Opels, VWs and possibly even Peugeot and Citroens.

The cards read: "What is wrong here? You like working for us. You are fond of your workplace and salary. But you are driving a competitor's car."

The cards have been signed by two executive board members as well as the head of its works council and invite workers to visit BMW's sales department requesting a test drive and details of how to trade-in a rival car for a new BMW or even a British-built Mini.

The campaign started three weeks ago and so far the response hasn't been exactly overwhelming: about 100 people have so far taken up the offer.