Walking can be really fun! Its a great way to incorporate health and fitness into your day and there are a range of useful resources online relating to walking and health including apps and programmes designed for the absolute beginners right up to the avid rambler.
Public Health England – One You
NHS - Active 10 walking
NHS couch to 5K
Transport for London also have a useful range of maps of routes to take in and around inner and Greater London, along with alternative tube maps that promote walking too.
Walk London Network
Health and walking
Map of distance between stations (in steps)
Length of walks between stations (in time)
Short walks that are quicker than taking the tube