They studied customers and their behaviour in about ten stores, and came to the conclusion that it was, as Ingvar put it, “a deplorable experience”. He later explained that this was what prompted IKEA to make a large bag to carry on the shoulder, hang on a platform trolley, or carry in your hand. Head of purchasing Lars Göran Peterson, or LGP as he’s known at IKEA, was tasked with measuring many of the items in the range that could be carried. This enabled him to work out an optimum size for the bag.

On a trip to Taiwan, Ingvar Kamprad and LGP found a suitable manufacturer. They had specified, for example, that the bag had to be large enough to carry rolls of wallpaper, and sturdy enough for 50 kg. A Taiwanese factory owner showed the men a sample of polypropylene, a material often used for large rice bags. Ingvar and Lars Göran were keen on the idea, but they wanted to be sure the bag wouldn’t break. “We found a woman at the office who weighed about 50 kilos and asked her to stand in the bag,” Lars Göran remembers. “I took one handle and Ingvar took the other. We lifted the bag up, and it didn’t break!”

That was how the yellow bag was born at a factory in Taiwan. But customers had exactly the same transportation issue after paying for their goods, so Ingvar wanted IKEA to make two bags of different colours. One would be sold at a very low price at the checkout so that customers had something to carry their items home in. And Ingvar could see an important knock-on effect as well. “Done right, the bags could be something that unconsciously brought people together, without having any advertising on the bag,” he later explained in a letter. “When they saw one of the bags on the street, at the beach and so on, they would know that they had something in common: a visit to IKEA. With tens of millions of bags in town, this could be excellent publicity.”