(Charles) Gordon Phillips was born in Slough, the son of a Baptist minister. He grew up in Nottinghamshire and trained as a teacher at the Nottingham University. He was passionately fond of the organ and from his teenage years dedicated his energies to passing professional examinations and writing for the instrument. As a composer, several solo works were accepted for publication before he had completed his higher education. He was a student of Ernest Bullock and John Ireland, and was a frequent recitalist in and around London. Following the war, his attention turned towards the editing of lost treasures of English organ music and the design of a new organ for his church, All Hallows, Barking, which stands by the Tower of London. Over the succeeding years, he went on to give more than 3,000 recitals upon the Harrison and Harrison organ there. As an editor, he is well-known for his important series, "Tallis to Wesley." As a composer, his works contain an astringency which can be bracing, even rather harsh at times.
I bought this music more than 30 years ago when I was a student at Peabody in Baltimore. There was an old music shop across the street, and this is where I bought it for the princely sum of $2.
From time to time, I would look at it, but every time I tried it, I'd give it up, as it's an "awkward and tricky" piece. You will need to decide whether or not you like it.
The plainsong hymn used is the famous "Urbs beata Jerusalem" (Blessed city, heavenly Salem), a melody that has a wonderful sweep to it, and has been used as a theme by many composers, most notably by E. C. Bairstow in his monumental anthem by the same name. To hear a quick bit of Bairstow's piece, here is a section sung by the choir of Ripon Cathedral, yours truly at the mighty Harrison! :-) (Go to 16:51
in the video.)
Musical notes in First Comment.
I dedicate this upload to our member Dabchurch! THANKS, David!