We have, of late, been in extended communication with Mr Martin Cummins –  an engineer in permanent magnets and a man of considerably piqued curiosity – amply demonstrated to us now that Mr Cummins has turned his inquisitive mind to the mysteries of the telegraph pole.

I bear only a query regarding the grey plastic extruded ducts often seen, placed 180 degrees apart, on telegraph pole bases. After years pondering on same, I finally came to the conclusion that they were either for adding preservative at intervals (Hence cap sometimes seen) or possibly, but unlikely, as an anti-rotation device for where a replacement pole was a close fit in an existing hole – even providing access for a below-ground wood rot check.

Upon request, Mr Cummins furnished us with example photos.  He went on to tell us that his approaches to “Outreach” proved less than fruitless and nobody there had the faintest idea what these “depthing tubes” were for. Though why he thought a mental health charity would be able to help, when coincidentally, right next to them in the phone book he would have found “Openreach” and perhaps a far more illuminating phone call.

He continued…

I have been told that it is a neat device for ensuring correct burial depth, even if the “Birth-line” is incorrectly stamped.  Is this the whole story? and was it an invention of the G.P.O? What is the correct name for the duct, and is the depth rod a purpose made, graduated scale, with perhaps a cursor to rest on the top of the tube, or just a piece of convenient bar, which is chalk marked? Presumably the reason for the height from ground-level is to discourage small children from gravel-filling (Caps as well) or is there another reason? Two tubes, I suppose, in case one gets crushed flat during installation? I have yet to see an article on this system?

Mr Cummins is very thorough in his research and determination to attain complete and total understanding of his subject.

While endeavouring to locate information on these ducts, I came across a reference to a spigot or flat circular mark called a “belly-button” being found on posts, which was put on the straightest side of the post. Perhaps another, humorous term for a birth-mark, but why it is orientated this way is beyond me. Another site refers to the birth-mark as a Doby mark. A strange term-any idea of its meaning?”

Mr Cummins also turned up a whole load of interesing telegraph pole patents; two shed loads about fibre-glass telegraph poles in Dunstable; a fine example of a telegraph pole preservative administering system near Leighton Buzzard; and another unponderable suggestion that BT may well fly kites to raise telephones line over a tree branch.

All of this though makes me think that Martin is looking just too hard – reminding me of the story of the millions of pounds that NASA spent developing a biro that could write in the micro-gravity of earth orbit – whereas the Russians just took a pencil… You see, I think the answer is much more mundane in that these tubes are just “kick stops”, cable protectors – and nothing more. Intended to save the hardship caused by fluourescently clad council grass-strimming staff from slicing through the cables that run vertically down the pole and into underground ducts. On the left is one I photographed near home showing a protruding wire.  Those as witnessed by Martin Cummins simply being devoid of cable.

I am, of course,  just guessing, and respectfully ask some of the many Openreach and assorted telegraph pole types who frequent these esteemed pages to espouse some of their profound wisdom and tell us, and particularly, Martin Cummins, what the hell these things are for?

Prompted by the picture that Brian Russell sent in 5 posts ago, reader Ernie Stanton sent in the photo you see at left – one of three such cast iron marker posts he found in Plymouth.

He says :

A contact at Plymouth museum gave me your details following an enquiry I made to him. I have found three cast iron maker posts in Plymouth, similar to the one on your website.

These are however slightly different, in that they carry the letters GR and have a line under the ft in. From the condition of the one shown on your website, it seems that this may have fallen off the one photographed by Brian.

The three in Plymouth are however identical to each other and have a recess under the ft in into which numerals can be fitted.The combination of an arrow underneath the horizontal line reminded me of OS bench marks, which are traditionally carved into the faces of walls etc., but these are not shown on the OS maps I have, dated 1892/4. If you ever discover what they are I would be interested.

Well Ernie, I consider myself a bit of a dab hand at internet researching, but I’m struggling to find much about these posts. The GR in this case standing for George Rex (ages it to between 1910 and 1936) whilst Brian’s being from V.R.Victoria Regina (1837 – 1901).  I will continue to search, but I’m going to  guess aged water mains rather than anything telegraphic.

Meanwhile however, my detective brain did spot the darkening stain at lower left, and which continues on to the pavement and surrounding wall – indicative, perhaps, that a disrespectful dog may well have passed this way shortly before Ernie took his photo. 

Elementary!