Back Hill Substation EC1

This imposing building presides over an entire block, in the back-streets of Camden. I’ve admired its austerity and unadorned walls, amongst the much more elaborate buildings around. This is an electricity substation, very functional. I’d noticed it while sketching The Coach, a nearby pub.

There were many more pipes and connectors than I could fit into the drawing. They all looked important. This is a serious building. The sign on the wall says “Danger of Death”. But the pipework has a certain lighthearted steampunk appeal. The arrangement has lamps, ladders and valves in odd places, and inexplicable vents, as though it might huff and exude puffs of steam. But when I saw it, the whole structure was silent and still.

The building is from the 1950s.

This complex dates mostly from 1956–7, when the London Electricity Board extended an earlier yard established in the late 1920s by its predecessor, the London County Council’s County of London Electric Supply Co. The 1950s buildings, designed by the LEB’s Architect’s Section, are of reinforced-concrete and steel frame construction with elevations of buff-coloured brick and glass block. They match the original building in the southeastern corner of the site ….

‘West of Farringdon Road’, in Survey of London: Volume 47, Northern Clerkenwell and Pentonville, ed. Philip Temple (London, 2008), British History Online https://www.british-history.ac.uk/survey-london/vol47/pp22-51 [accessed 11 September 2025].

It is very much in active use and currently being enhanced. Planning notices fastened to the main gates informed me that:
“The customer at 21 Moorefield’s [sic], London EC2… requested a 10MVA supply from the City of London 33kV network providing enhanced level of security of supply.”
They don’t want any fluctuation in the power supply, then, and no power cuts.

At the moment:
“Back Hill 33KV substation does not currently have adequate capacity headroom to fully meet the customer’s requirements…” and “The substation capacity is currently limited by the transformers, incoming 132kV circuits and 132KV switchgear..”

So they have to replace the transformers, cabling and switchgear, to “allow the 21 Moorefield’s customer connection,” the notice says.

21 Moorfields is the building above Moorgate Elizabeth line station, just to the East of the Barbican.

“Electrical Contracting News” provides a more general description:

Almost 10,000 customers from Farringdon, Clerkenwell and key buildings in City of London are to benefit from a multi-million pound investment to upgrade the electricity network.

Work is currently underway to install the first of three new transformers – a device which steps down the power voltage so electricity can be safely delivered to local properties. The transformer, along with new switchgear equipment, will be installed at UK Power Networks’ substation to meet greater energy demand in the area.
The £24 million project started in October 2021 and is due to finish in early 2026. As part of the scheme, the firm has consulted local councils and other interested parties to ensure that people experience as little disruption as possible while the work takes place.
Euan MacRae, Project Manager at UK Power Networks, says: “This substation upgrade is part of our ongoing investment in the network to maintain safe and reliable power supplies and future-proof the network. The City of London is home to some of the capital’s most iconic buildings, so in collaboration with our alliance partner The Clancy Group this project is committed to carrying out a staged replacement of the major electricity assets at Back Hill Substation, some of which date back to 1956 and have been well maintained over the years.
“We are excited to be installing innovative equipment which will allow the substation to provide double the previous level of power and will improve the resilience of power supplies across the network in London.”

Electrical Contracting News, April 2022 (https://electricalcontractingnews.com/news/city-of-london-residents-to-benefit-from-24-million-power-scheme/)

I was pleased with my sketch of the substation, and I enjoyed trying to follow the lines of the pipes.

I find it fascinating to realise that there is enormous work going on to keep the electricity flowing, with very little fanfare. There are these silent buildings sitting amongst the offices and flats, doing their job.

Here is a sketch map to show where the substation is:

I’ve sketched the nearby pubs, the Gunmaker’s Arms here, and The Coach here.

I’ve sketched another substation here:

City Road 400kV Substation EC1