Germany is celebrating National Currywurst Day, on what is the 70th birthday of its favourite street snack.

Comprised of pork sausage topped with a mixture of curry powder and ketchup, it is estimated that Germans eat 800 million currywurst every year, 70m in Berlin alone. But this national staple has a surprising British connection.

Inventor Herta Heuwer obtained the ketchup and curry powder that inspired her recipe from British soldiers stationed in Berlin in 1949. Heuwer started selling her condiment-heavy concoction from a street stand in the Charlottenburg district, catering mainly to construction workers rebuilding the war-ravaged city, and selling up to 10,000 servings a week.

Heuwer called her sauce "Chillup" and patented it in 1951. She died in 1999 and in 2003 a commemorative plaque was dedicated to her on the corner of Kantstraße and Kaiser-Friedrich-Straße where she had her kiosk, with the inscription: "Her idea is a tradition and an eternal pleasure." On what would have been her 100th birthday in 2013, she was honoured with a Google Doodle.

Reuters

Currywurst is popular across Germany, although perhaps most famously associated with Berlin, and regional variations include paprika and chopped onions, while halal food stands serve the dish with beef sausage in place of pork.

Volkswagen's worldwide headquarters at Wolfsburg in northern Germany, the largest manufacturing plant in the world, even has its own currywurst production line – the spicy snack is item number 199 398 500 A on the official parts list and has been made at the factory for 45 years. Volkswagen makes seven million currywurst a year, and German dealers often give packs of the snack to customers as gifts.

Georg Bier, owner of a snack stand in Berlin, explains the finer points. "The most important thing is a top-quality sausage. We also put beef into our sausages and we have fresh deliveries every day. Then, of course, we have our home-made hot sauce, or curry ketchup, and the whole thing is a flavour firework.

"I think the currywurst has become part of Germany's cultural heritage. All of Germany is represented here. It's a great success story."

Customers Janine and Jim Browning are equally convinced of currywurst's cultural significance. "We just found out that it's 70 years old... And 30 years since the wall came down this year. So it's a big year, 2019."