As of 2019, where in the UK would you find the oldest passenger trains in regular daily service?

Grace, they were old District Line stock as these were the only stock which could fit through the existing tunnels. These were replaced in 2019 and the old carriages were made good and now housed in Train Story Discovery Centre at the Isle of Wight Steam Railway.

wrong answer. isle of wight has been using old London Central line trains, discarded by London. Just now being replaced.

Thanks for the info. Always glad to learn something new. Brought up in GWR land myself so like railway related questions.

Love the island.