Fancy a straight forward walk? Why not walk part of the Northern line from Tooting to Clapham. It is not a lengthy walk, just over 3 miles and it takes about 1 hour. You can see a lot though and you can shorten or extend it depending on what you fancy. It takes you from Tooting, which is filled with flavour and a bustling high street, into a more suburban area, then into Balham filled with trendy shops and then past Clapham South onto the Common.
The walk is essentially a straight line. You come out of Tooting Broadway station and then turn right along the high street. Then it is a straight line all the way up to the common. There are plenty of places you can stop along the way for a cafe, brunch or a drink. And there you have it a simple pre lunch walk to help get you some fresh air.