Sir – Your correspondent Martin Murphy (Letters, January 14) who was offered a “venti” coffee at the Radcliffe Eye Hospital should have realised that “venti” is Italian for 20, and so he was being offered 20 fluid ounces, or what we would call a pint.

At least, it would be if these were the old Imperial fluid ounces, but they might be either “US customary fluid ounces” or “US food labelling fluid ounces”, so the volume might have been 568.26ml (one Imperial pint) or 591.48ml or even 600ml. It isn’t clear.

It seems to me that any of these is an unsuitable amount of strong coffee to offer to hospital outpatients, and very considerably more than is customarily consumed in Italy.

However, if the venti coffee drink is a cold one, Starbucks are said to give you 24 fluid ounces for good measure and include an extra shot of espresso as well!

Another chain which gets away with using American units in Britain is Subway, although on the Continent they have had no difficulty in going metric, calmly offering 30cm sandwiches.

McDonald’s expects us in England to know that by “fudge” they mysteriously mean chocolate, yet on the continent they use “chocolat” and similar words.

Even in the USA, there has been concern over some “foot-long” Subway sandwiches which only measured 27.3 cm (rather than 30.5 cm = 12 inches, so they were 1¼ ins too short). Many young and/or foreign customers in London and Oxford have little idea what “six inches” or “one foot” means anyway, so in England they might as well call them vaguely “piedi”, I suppose. Would that help?

Roger Moreton, Oxford