There are plenty of the Thorn (and also GEC) aluminium columns from the 1960s including 8m versions, that are still around particularly in private installations, which testify to their durability. Steel columns less than 20 years old have been documented of failing structurally. There is no reason to suggest that aluminium columns should have a shorter lifespan than alternative types.

Those Thorn Alu columns will go on and on for a long time, the only thing that will shorten it's life span is being hit or dented.

I would have thought aluminium columns would last longer due it being a less reactive metal than steel therefore less corrosion will occur. The only thing about aluminium is that its extraction from bauxite is very energy intensive so its probably less environmentally friendly than steel. At least if there's ever an aluminium shortage we will be able to melt down all the alu columns.

Don't forget plenty of iridiums to melt down for that

I would image that if iron was present in the surrounding ground, then aluminium columns may suffer then?

I wouldn't be too sure Claire, if it does it wouldn't be a good idea to plant any in my area due to it being home to the largest steel works in the world in the past and the ground being quite rich in iron to start with. Iron and steel are more reactive metals than aluminium and copper for example. I can't think of any reason why it would cause them to corrode quicker.

Aluminium is a mild soft metal where as iron and steel is slightly heavier. When aluminium is used in iron rich areas, the iron is essentially 'grit blasting' the aluminium layers to virtually nothing overtime thus causing weakness in the aluminium column.

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From streetlighting to radio, dance through the night whilst the streetlights are glowing outside.

I think the Thorn and GEC columns from that time were generally built better than those of, for example, early 1990s lineage. My family's hailing town has loads of 10m alu columns from the 60s and 70s and they're doing fine.

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And steel making uses massive amounts of energy as well. However production of both metals uses recycled material so there is probably not much in it.

I remember reading somewhere because of recycling there is a world surplus of aluminium.