Group walks
Walking in a group has the advantage that there is usually someone to lead the way - and it is also a great way of meeting people. If you are interested in joining a walk with a group, a couple of options are available, which I describe below.
The downside of walking with a group is, of course, that you have to make sure that you are on time to meet up with the group and to go at their pace/style of walk. I say “style” because people have different approaches to walks - notably about whether and for how long you are going to stop for lunch. You would be surprised by the number of different ways in which people choose to walk.
Time Out Saturday Walkers Club
The Saturday Walkers Club organises several walks per week which are free to join and advertised on their website. Their website also includes details of over 300 walks. The walks are all public transport friendly and start and finish at a train station. They are open and welcoming to all.
However, the walks often start fairly early in the morning and are usually for fairly serious walkers - you might find it difficult to keep up if you are out of shape. There is also quite an emphasis on pub visits - both for lunch and after the walk. This can be difficult if you just want to eat a quick sandwich and carry on.
Ramblers
The Ramblers, of course, are a wonderful institution and there are all kinds of groups to join. Amongst those is the Chilterns Weekend Walkers group, which organises regular walks in the Chilterns.