The creation of writer William Donaldson
Do your Google search on
henry root
and the first reference is the one you want
Of course, there are many real-life people of that name.
A "Wet Fish" magnate.
I have a book entitled "The Henry Root Leters" published by Weidenfeld and Nicolson in 1980 ISBN 0 297 77762 9. It contains letters written by "Henry Root" to various personalities and organisations and their replies. It is very funny but probably rather dated now.
Years ago my husband had a thing about this Henry Root and bought more than one book I seem to remember. He was writing mildly provocative letters to various people and (if they fell for it and sent him a reply in earnest) he was publishing his letter and their replies. My husband thought it was hilarious whereas I found it really boring!
Quite some time on the box there was a series of about six episodes where the central character I am sure was called Henry Root and he was played by George Cole, it was an absolute hoot and I would love to watch it again.