  This paper presents (H-alpha + [NII]) imaging and spectroscopy of a
previously unknown, highly evolved planetary nebula of low excitation. It was
discovered serendipitously from AAO/UKST H-alpha Survey images as part of a
project to exploit the survey data and has evaded detection by previous surveys
due to very low surface brightness. It is a remarkably annular planetary
nebula, some 19' across, making it one of the largest examples of its type. We
estimate a radius of 1.5 pc and a distance of 550pc as derived from a new
H-alpha surface brightness - radius relation. PFP 1 has near perfect circular
symmetry, broken only at the NW edge which is coupled with significantly
increased (H-alpha + [NII]) intensity. This indicates an early stage of an
interaction with the interstellar medium. A blue central star candidate has
been identified from the SuperCOSMOS Sky Survey data.
