I didn't have a baby in London, but I'm in Chicago and my baby was on/off public transit a lot and walking around city. I preferred baby wearing plus very lightweight stroller combo. Often, I didn't even take the stroller. Much easier to just have him strapped to me when trying to push through train stations and up/down stairs to subways, etc., and then my hands were free as well. I preferred a stroller that I could fold up and tuck under table at restaurants and not bother other customers.