Our occasional pieces on ambiguous and solecistic signs have attracted a good response from readers similarly offended by linguistic imprecision. Luela Palmer finds her favourite horror over some meat shops: "Pork Butcher - Family Butcher". She also warns, in case anyone should think of uttering it, that "They both thought they were right" does not mean the same as "Each thought he was right."

This has a bearing on the line that causes me to lose concentration on the plot of almost any television police drama. When the sergeant is ordered to "position a man at either end of the street", surely his correct action is to select one end of the street, then put a policeman there. Invariably, however, he seems to station one man at each end of the street - and he is never reprimanded for it.

B.J.Caston mentions a BBC radio announcer ending one recital with the words: "... and next week, pianist X will play Mozart and Schubert at the same time - one o'clock Monday". His all-time favourite, however, is a sign spotted some 40 years ago in a shop window in Newport: "Sound Reproduction Equipment For Hire".

Alan Baker mentions the phrase "not to mention" which is invariably followed by mentioning the unmentionable. As he points out, it is probably an unintentional substitute for the intended "not forgetting". Sadly, such a misuse will not leave our language until the day comes when a television presenter says: "Our next guest needs no introduction" and proceeds not to give him one.

The problems of "owing to" and "due to" have been raised in a number of letters and still clearly give rise to a good deal of confusion. The situation, however, ought to be simple: "due" is an adjective, and needs to have a noun attached to it. "Owing to" has assumed the function of a compound preposition. "Owing to the size of our postbag, this column is longer than usual" is correct. "The unusual length of this column is due to the size of this postbag" is also correct. But "Due to the size of our postbag, this column is longer than usual" would, strictly speaking, mean (if it meant anything) that the column itself, rather than its length, was due to the size of the postbag. Shame on all of you who advocate using "because of" to avoid the problem. That's an ugly cop-out.

Still on the subject of "due" Rufus Isaacs tells us of the video display at his local station which displays, if the train is running on time, the words "on time". But if the 10.04 is, for example running five minutes late, it will read "due 10.09", which, quite rightly, worries him. For however late the 10.04 may be running, it is (or was) still due at 10.04. The sign should say "expected 10.09". Mr Isaacs could easily have been driven to drink by this error, if it were not for the fact that his local pub has a sign on the door saying "Guide Dogs Only".

It all reminds me of an experience when I was checking in for a flight at Heathrow on a day of much air traffic disruption. "Is it expected to leave on time?" I asked.

"Yes," replied the check-in girl, "the flight will leave on schedule at 12 o'clock."

"But it's scheduled for 11 o'clock," I said.

"No sir. Owing to delays, your flight has been rescheduled for 12 o'clock and is now expected to leave on time." Well, at least she said "owing to".

Back on the rails, however, why do they persist in advertising "regular services to London"? Once a year is regular. Where we need reassurance is in their frequency, not regularity.

Graeme Kenna laments the demise of his once-favourite road sign. Beside the main Runcorn-Widnes road, it used to read: "Sudden unexpected noise likely". Marjory Watson was more alarmed by a sign saying "Heavy Plant Crossing" which had her scanning the area for triffids. J.P.Watts warns of the sign in Middlesborough saying "Humped Pelican Crossing". He did not catch sight of the bird.

Mollie Caird, while rejoicing in her vision of clapped-out executives retiring to a "Tyre and Exhaust Centre" asks why everything has to be a "Centre" these days. I have always particularly liked Neighbourhood Centres, which seem to get you back where you started. Bill Fowler is more concerned about adverts that require a "part-time woman".

Finally, Peter Morris has not plucked up the courage to ask what the sign on the top shelf in his newsagent means when it says: "No Flickering" and whether it refers to the brightness of one's eyes when browsing the magazines, or one's trouser-leg alignment.

William Hartston