10 JULY 1993, Page 23

Tertium quid

Sir: Lunching at Buck's on Referendum Day 1975 with the late and much lamented Toby O'Brien, I was informed by the bar- man that an authentic Buck's Fizz required, in addition to champagne and orange juice, a portion of grenadine. Whether or not this is the fabled secret ingredient referred to by James Rolls (Letters, 26 June), I've cer- tainly made frequent and effective use of it in the intervening years. Basic sirop de grenadine renders the mixture a mite too succulent for my taste, and I personally favour a dash of the alcoholic cordial which (in at least one domestically produced man- ifestation) goes by the name of Old English Grenadine. This not only increases the potency but deepens the hue of the result- ing substance.

P. L. Dickinson The College of Arms, London EC4