Most columns in England are either made of Cast Iron/Aluminium/Galvanised steel, Concrete or Wood.
METAL
Used in main/newer roads. Most nowadays are galvanised (protected from rusting). However older columns may still be susceptible to corrosion, especially cast iron columns that are now of 100 years old or even older. They range from small 2m+ columns (used in illuminated signposting) to gigantic 20m+ columns for powerful floodlighting.
Abacus have a special metal column that can collapse to provide easier access to the lantern, and prevents vandalising of the door compartment. This column is seen in areas where there is no access for a maintenance platform. Stainton has a similar column. It doesn't actually collapse, but half way up there is a hinge that allows the top part of the column to spin round, making the lantern go upside down by the base of the column. (These columns will not collapse on their own. They require special tools and hydraulic lifting gear to drop, so don't worry, they are unlikely to fall with you standing underneath them!)
Known makers of metal columns are: Fabrikat, Abacus, British Steel, Urbis, Stanton, General Electric and BEI.
CONCRETE
Used in quieter/older/rural roads. Concrete columns started appearing in the 1950's, replacing cast iron columns. They continued to be made right up to the 1980s. Most concrete columns were designed for Top-Entry style lanterns (The older style version of a Thorn Beta 5 is a perfect example of this) and therefore create a problem when replacing a top-entry lantern with a side-entry lantern. Most councils nowadays have had the top-entry brackets removed, replacing them with galvanised steel sleeves, occasionally painted.
This is also done as some of the brackets are in bad need of repair as they are spalling (being eroded by continuous wearing with moisture etc.) and could pose a threat to the public if they fell. These metal sleeves eliminated the threat of this occurring to a minimum. Some of the metallic door compartments are also now starting to show signs of age due to traffic, plants growing on them and the various deeds that dogs do on them! So these sleeves can sometimes be seen around the foot of the column.
These metal sleeves eliminated the threat of spalling occurring to a minimum. Some of the metallic door compartments are also now starting to show signs of age so these sleeves can sometimes be seen around the foot of the column. They range from 5-6m columns to about 10m columns. Anything after that would have been made of metal.
Known makers of such columns are: Stanton & Staveley and Concrete Utilities Phosco (Usually abbreviated to just CU).
I have recently seen a CU 5m column lying on the ground with a top entry 55w SOX GEC lantern. It was used (in its vertical days) to light a small footpath before a bypass and new houses were built on it. The lantern was completely rusted up, no lamp or bowl and the door compartment on the column was cracked - but interestingly the door was galvanised on the inside but not on the outside. I would probably have taken the column there and then (and as I think about it now, I should have done - it was removed the following day) but it was extremely heavy, and it had a dangerous looking break in it from falling and the wires had almost completely perished from exposure. I didn't even manage to get a photograph of it. Damn!
WOOD
Used on very rural roads where concrete or metal columns would not be suited. The 'columns' usually double up as telephone pylons and have a small, nailed in lantern holder with wires leading to a control-gear box further down the column.