The Daily Telegraph has an article based on a new volume in the English Surnames Survey series, The North Through its Names: A Phenomenology of Medieval and Early-Modern Northern England by Dave Postles
It's fairly well known that Mc, Mac, Fitz, O' and ap are British surname prefixes, and "son" and "s " suffixes meaning "of" in the sense "son of" or "daughter of" or "family of." I was not aware that the suffix "son" generally has northern English roots, while similar surnames with "s" on the end indicate southern English ancestry.
I checked this out using Stephen Archer's British 19th Century Surname Atlas, which is based on the 1881 census. Adamson, on the top left, and Adams, bottom left, show the pattern, as do Johnson and Johns on the right. You can easily try this yourself with the online surname distribution facility on the new National Trust Names site. Try Roberts and Robertson.
Postles' book is 208p, published by Oxbow Books in 2007) ISBN-13: 978-1-84217-176-9 ISBN-10: 1-84217-176-3.
There's an excellent Modern British Surname web site worth reviewing. Those not intimidated by statistics will especially appreciate it.