As the country developed its own mobile payment system, called Swish, banks slowly stopped handling cash, and tills disappeared from shops.
With cash circulation the lowest as a share of GDP in the world, Swedish progress was lauded, and observers wondered how it had forged so far ahead of the rest of Europe so quickly.
Realising that reliance on an electronic payment system left Sweden vulnerable to blackouts or sabotage, the Riksbank – Sweden's central bank – urged civilians to keep 1,000 Swedish kronor (£80) per adult at home.
The government issued a brochure entitled "If Crisis or War Comes" to every household, advising Swedes to use cash regularly to "strengthen preparedness".
