Postal Museum & Mail Rail

London's best rainy-day secret. Ride the Mail Rail — the world's first driverless electric railway — through the original tunnels 70 feet below the streets, which once whisked four million letters a day between Paddington and Whitechapel from 1927 to 2003. The 15-minute ride runs through open-top miniature carriages with audio-visual storytelling along the way, then it's up to the museum galleries for interactive exhibits spanning five centuries of postal history. The current family exhibition, The Jolly Postman, runs into January 2027, bringing the classic picture book to life through an interactive story world. There's also Sorted!, a separate-ticket play space for ages 1–8, if little ones need to burn energy after the ride. The museum and Mail Rail sit in two separate buildings across Phoenix Place from each other, so head to Mail Rail first and check in ahead of your printed time slot. Book online in advance — timed Mail Rail slots regularly sell out on weekends and school holidays.