If you have a tiny dog that fits in a bag, absolutely go for it. It’s fun, it’s practical, and you’ll become the most popular person on the train. But if you have a gentle giant like a golden retriever or a husky, my advice is: just take the bus. Buses are dog-friendly all day, every day, and nobody will judge you for the shedding.
And if you do attempt the Tube with a big dog, bring treats, a portable fan, and a sense of humor. Because when your dog decides to lie down in the doorway of a packed carriage, you’re going to need it. Good luck, you glorious, mad commuter.