“The number you require is Oh! One! One! Six . . .” barked the tin brain as you fumbled for a Biro.

No sooner had you learned to expect the Dalek than BT re-wrote its script. “The number you requested” now put the blame on the caller. “You asked for this number,” it seemed to say. “So don’t come whining to us if anything goes wrong.”

Give me a phone book any day. With a phone book, no one insists that you narrow your search down to a pinprick. You may wander where you will. Stroll through Yellow Pages and you’re likely to pick up more than a number. Yesterday, for instance, I learned about shot peening. When I entered the directory in search of shoes, I was as familiar with peening as Dante was with hydrolastic suspension. But you know how it is. You open the book at “Taxidermists”, flip back through “Suede goods” and “Slaughter houses”, and just as you’re about to hit “Shoe shops” you land on “Shot peening” and fnd yourself staring at it helplessly.

Is it a misprint? Should it say “Shop preening”, and would it help much if it did? In the end, I decided that “shot peening” was probably in the same category as “Capstan repetition work (see precision engineers)”.

Along with “section bending” and “mill cleaning”, these were no doubt the sort of processes on which the wealth of the nation was founded and which still go on quietly while the rest of us are shopping.

Not that shot peening sounded quiet, exactly. The note to “see under sand blasting” suggested streams of shot fired at steel. Does the shot make “peening” sounds as it flies off? Suddenly, I just had to know.

Swapping directory for dictionary, I confirmed that peening is indeed a method of “working the surface of metal with a hammer or by blasting it with shot”. Also that a “peen” is the tapered end of a hammer head. Far from being onomatopoeic, then, “peening” comes from the Latin pinna meaning point. Well I never.

Talking of points, where was I? Ah yes. Shoe shops. The number I requested was . . .