This is a hand-made Christmas card sent by Peter Tranchell to friends and members of the choir in 1978...
The card seems to have accompanied PAT's pre-term letter of December 1978, which included the following:
The Precentor is not given to sending Christmas cards, but happening upon some copies of an erstwhile pictorial effusion thinks you might enjoy a little conundrum not necessarily for exhibit on mantelpieces. It is a pastoral scene of some antiquity, when shepherds did their seasonal "abiding" (whatever that may have been, and one may have one's suspicions). The celestial choir (which had been slightly delayed by having to pick up cassocks & surplices from King's en route) passed overhead several times. On their return flight their motto was suitably changed from 0.B.C. to 0.A.D. Herod, who was disguised as sheep no. Φ with a view to getting closer acquaintance with the shepherds (an old old trick) was the victim of sheep-rustlers later in the small hours, which put him in an ill humour for most of holy writ.
Anyhow, it is a token of precentorial best wishes for the restive/festive season, and brings with it the admonition to be careful how you eat too much mistle-toe or get hung/hanged with paperchains.