According to the February 27, 1958 issue of The Springfield News Leader, the Gillespie Pendulum Putter was devised in the mid-1950s by Percy Gillespie of Dublin, Ireland. Designed to be used in a pendulum fashion, with the golfer straddling the ball and placing both thumbs on the front of the flat shaft, this club measures 24 3/4" in total length.
In the 30 September 30, 1965 issue of Golf Illustrated, Henry Longhurst commented on croquet-style putters ". . . the best
to my mind was that of a M. Gillespie of Dublin, which having been
specifically ruled legal, was suddenly banned, much I believe, to his
advantage, since he had insured against this. You bent down with your
two thumbs level on the front of the handle and swung the putter,
pendulum-fashion, between the legs. The inventor held that his was the
only position which with the human body could provide a true pendulum
action and I suspect that he is right. The club, if such it may be
called could be devastatingly accurate and I believe that Harry Bradshaw
became so good with it that he might have won everything if he had had
the nerve to appear with it in public."