It even has its own part number.

What product does Volkswagen sell more of than any other? The Golf? Perhaps. The Beetle? You'd think so. The Transporter? Good guess again, but no.

Volkswagen's best-seller isn't a car, or a van. It is in fact a sausage.

That's right. Since the 1970s Volkswagen has produced Currywurst sausages on-site at its Wolfsburg factory. The sausages are primarily consumed by the company's employees, but are also sold further afield.

Last year Volkswagen produced 6.2 million cars at its factories across the world – there's more than 50 of them. Meanwhile the sausage factory on the Wolfsburg property alone produced 6.8 million sausages.

Volkswagen Wolfsburg

But why does Volkswagen, one of the biggest car manufacturers on the planet, also produce meat products? While Volkswagen has produced food for its employees at the factory since the 1930s, back in 1973 the carmaker decided that it would be more cost-effective to produce the sausages eaten by its employees on-site.

The success of the sausages, eaten by tens of thousands of Volkswagen employees, has led to them also being sold in a dozen other countries.

The unorthodox part of the Volkswagen operation was recently profiled by The Grand Tour host Richard Hammond in his new Discovery series Richard Hammond's Big.

In a segment on the show, Hammond joins in with the production process, drawing comparisons between the sausage production line and the car production line next door.

The former Top Gear host also meets 50-year Volkswagen veteran Sigrid Weinmann, who started her career stitching interiors for Volkswagen cars, before eventually ending up working in the sausage factory.

Funnily enough, the Volkswagen sausage can be found in Volkswagen's parts directory. So while you're looking for replacement bumpers, headlights, and the like, check out part number 199 398 500 – just in case you're feeling a little peckish.