What is the definition of 01 023?

"Let's break down the mysterious '01 023'. It's not just a phone number, it's a digital footprint that's probably been tracked by a ghost, or maybe your pet cat. Now, here's an edgy example: 'The janitor found the 01 023 in the trash, claiming it was a haunting relic from the '80s'. Sounds like a bad Halloween costume gone wrong, right?"