TSB, legacy IT
Back in 2004 I remember visiting the head of an IT department that had responsibilities for TSB's IT. There was an enormous system map diagram on a huge whiteboard in the guy's office, it wasn't pretty with lots of old systems cobbled together that somehow just 'worked', many undocumented and originally written in house. The challenge back then was that the IT team had an average age of 55 and final salary pensions that were going to kick in at 60, it was a ticking time bomb some 14 years ago...