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Thirty years ago years ago, in March 1995, a fresh-faced Claudia Hammond arrived at the Â鶹ԼÅÄ for a job interview as a trainee science producer. It was a big opportunity so she prepared meticulously. She put together a comprehensive list of science and health stories, ready to pitch at the interview to show that she knew a good science story and would be perfect for the role.

Fast forward thirty years and Claudia, now an award-winning broadcaster and presenter of Radio 4’s All in the Mind, is sorting through the drawer of recycled scripts, briefs and notes she keeps to re-use in her printer. Right at the bottom of the inches-thick pile she comes across the list of stories she’d prepared to pitch at that interview three decades earlier.

In this quirky, personal journey, Claudia revisits five ideas from her Ideas List to find out what happened next. She tracks each headline-grabbing story forward through the false-starts and dead ends, the surprises and successes. And she asks what each tale teaches us about the tortuous path of scientific progress.

In this episode Claudia picks up on a story about the FBI, the United States’ domestic intelligence and security service. By the mid-1990s the FBI had 200 million fingerprint records, all kept on individual cards and stored in filing cabinets which took up an acre of floor space. Searching through these records could take so long that police were forced to release suspects before a match could be found.

The FBI’s fingerprint system was clearly - and urgently - in need of digitisation so that it could be kept as computer records. But because each individual record needed a lot of computer memory, an acre of filing cabinets would simply be replaced by an acre of computer servers!

Enter Chris Brislawn from the Los Alamos National Laboratory in New Mexico who devised a radical new data-compression system. He tells Claudia how he made the breakthrough using the mathematical theory of wavelets. This allowed the important information about a fingerprint to be separated from the unimportant information and, as a result, vastly reduce the file size.

And the system Chris invented is still used by the FBI today As Craig Watson from the US National Institute of Standards and Technology attests, it was an example of the right idea at exactly the right time.

Producers: Florian Bohr and Jeremy Grange