Search london history from Roman times to modern day
A bit out of date, but this interactive map of step free London is very good
Great Portland Street is not accessible to wheelchair users due to stairs between the platform and street level. There are either 41 or 42 steps. Too many steps.
All the London railway stations :
Underground lines : Hammersmith & City, Metropolitan, Circle.
Accessibility friendly : Great Portland Street is not accessible to wheelchair users due to stairs between the platform and street level. Either 41 or 42 steps.