From handbags to drug gangs to central banks – one of Britain’s finest investigative reporters reveals the surprising links in a global chain of crime

Question: why, if almost half of us now use cash only a few times a year, are high-denomination banknotes being printed in increasingly large numbers? In April 2024, the value of all the dollar bills in circulation reached an all-time high of $2.345tn, and may well be even more than that by now. The total value of dollars in the world has doubled every decade since the 1970s. Similarly, there are 1.552tn euro notes in circulation, while most other currencies – the British pound, the Japanese yen, the Swiss franc and so on – are all at something like their highest levels in history. This at a time when so many of us have pretty much stopped using cash altogether, and even the people who sell the Big Issue in our streets are equipped with card readers.

When I talk about “us”, I mean those who don’t have to worry about hiding huge cash profits from drug dealing, people-smuggling and so on. And that of course provides the answer to the question: while law-abiding citizens like you and I have to jump through hoops when we move even relatively small sums around for entirely legitimate reasons – buying a fridge or a secondhand car, say – drug dealers just shove bundles of the stuff into their coat pockets or suitcases and whisk them round the world in order to keep their business going. The number of dogs trained to sniff out cash at international airports is growing, but nothing like as fast as the rate at which big-denomination notes are being pumped out by the world’s central banks. And the ways in which money is laundered are growing in complexity and sophistication.