Hey! It was so great to see someone else was fascinated enough to be looking for this one. Partly thanks to you, I've found it, after frequent episodes of wishing I could get my hands on it. It came up on my very first day of first-year English at Wits University in Johannesburg, South Africa, in 1982. I never kept those notes, but often wished I had, just because they contained this poem! I found the full text at:

www.haileybury.herts.sch.uk/english/Schemes%20of%20Work%20Removes/ Anthologies/collated%20all%20sections.doc.

Here it is, for those who are still interested:

Discretion - Roger McGough (1968)


DISCRETION
(Roger McGough)

            Discretion is the better part of Valerie
            (though all of her is nice)
            lips warm as strawberries
            eyes as cold as ice
            the very best of everything
            only will suffice
            not for her potatoes
            and puddings made of rice
            Not for her potatoes
                        and puddings made of rice
            she takes carbohydrates
            like God takes advice
            a surfeit of ambition
            is her particular vice
            Valerie fondles lovers
            like a mousetrap fondles mice
            And though in the morning
            she may whisper: "it was nice"
            you can tell by her demeanour
            that she keeps her love on ice
            but now you've lost your hardearned heart
            now you'll have to pay the price
            for she'll kiss you on the memory
            and vanish in a trice
            Valerie is corruptible
            But known to be discreet
            Valerie rides a silver cloud
            Where once she walked the street.