Sir – At two central Oxford fast-food outlets recently I asked for small “fries”, a specified main dish and a large black coffee.

Simple enough. But at the first one, I noticed that that the till showed “medium fries” and “regular coffee”. When I queried this, there was some discussion about what constituted what they dogmatically call a “meal”, but I had not used the word “meal” at all.

In trying to rearrange matters for my benefit, the salesman and his manager somehow charged me extra for a separate tomato dip which I had never asked for, and in the end they seemed quite unable to cope with the problem, so I retrieved my money and moved on.

At the second enterprise, there was (to their credit) no problem selling me a large black coffee, but again “medium fries” appeared on the till, without comment.

When I queried this, I was told firmly that small fries only come as part of a specially named children’s meal.

When I pointed out that “small fries” is individually listed on the price list on the wall (as it had also been at their competitor), the salesman immediately gave way, and “small fries” with the correct price appeared on the till. “Happy now?”, he asked sarcastically.

Well, yes, happy enough at the time, I suppose, but not entirely happy. This is a small matter of course, but I don’t think it’s a very good idea (put plainly) that these places should trick people into eating more chips than they want.

Roger Moreton, Oxford