From Electric Arc Lamps in Bristol, by Peter Lamb, a supplement to the Histelec News, August 1997:

In looking at old photographs of late Victorian or early Edwardian scenes, many of you may have noticed very decorative street lights gracing the foregrounds. These lamp standards had long cylindrical shapes above the lamp, which distinguished them as being electric arc lamps. You may have wondered, like me, what was inside these housings. These cylinders, known colloquially at the turn of the century as “chimneys” were not chimneys at all, but housed the complex mechanisms regulating the carbon electrodes. Only two lamp standards of this distinctive design remain as street furniture on the Bristol streets and these are situated at The Mall, Clifton Village.

Given the long cylindrical shape and the fact it's on the Mall, pretty sure this must be one of the last two electric arc lamps still standing, or possibly the last one, as I couldn't find the other one.

EDIT: Having asked on Next Door, where there've been a few threads about historic lamp restoration, it seems the other one used to stand at the end of West Mall, not far away, was taken away for restoration a long time ago, and has yet to reappear.

There's another Bristol connection too, with Sir Humphrey Davy, as the article continues:

Sir Humphrey Davey is credited with inventing the first arc lamp, when he demonstrated his invention at the Royal Institution in 1810. It was powered by batteries and used charcoal elements enclosed in a vacuum. The vacuum allowed a longer arc with a much higher voltage. It was some years later (1844) that the principle was further developed by a Frenchman by the name of Foucault. He used carbons from the retorts of a gasworks, which were more durable. Thomas Wright devised the first arc lamp which involved adjustment of the carbons automatically as they burnt away, and W.C.Staite used an electric current for the regulation of the carbons. Foucault responded in 1858 by producing his regulating lamp.

(Yes, that is Foucault of Foucault's Pendulum fame.)