SIC code 35120 covers transmission of electricity businesses. With 427 active companies, this is a specialised niche within the UK business landscape. It falls under Section D (Electricity, gas, steam and air conditioning supply) of the UK SIC 2007 classification system, which is used by Companies House to categorise all registered businesses.
See the full industry analysis on the Transmission of electricity industry page.
With a 87% survival rate, this sector shows strong business longevity. Only 2 of 489 companies registered under this code have dissolved, well below the UK average. Companies in this sector average 8.4 years old, reflecting a balanced mix of established businesses and newer market participants. Growth has been exceptional recently: 46% of all active companies were formed since 2020, marking this as one of the fastest-expanding classifications. The 2010s contributed another 39%, meaning the vast majority of businesses are relatively new. The leading locations for this sector are LONDON (123), GLASGOW (13), CHELTENHAM (11), which together account for 34% of active companies.
SIC code 35120 stands for "Transmission of electricity" under the UK Standard Industrial Classification (SIC 2007) system. It belongs to Section D — Electricity, gas, steam and air conditioning supply. Companies use this code when registering with Companies House to indicate their primary business activity. The code is required for annual confirmation statements and is used by HMRC, ONS, and other government bodies for statistical and regulatory purposes.
There are currently 427 active companies registered under SIC code 35120 in the UK, out of 489 total registrations. This gives a survival rate of 87%, meaning 13% of companies registered under this code have since dissolved. These figures are based on Companies House data and updated regularly.
The top locations for transmission of electricity companies (SIC 35120) are: LONDON (123), GLASGOW (13), CHELTENHAM (11), BELFAST (6), PERTH (6). Geographic concentration can reflect local economic conditions, industry clusters, or proximity to key markets and supply chains.
The sector is growing: 46% of currently active SIC 35120 companies were formed since 2020, and 39% during the 2010s. This sustained formation rate indicates ongoing demand for transmission of electricity services in the UK.
Companies classified under SIC 35120 have an average age of 8.4 years. This suggests a balanced sector with both established players and newer entrants. Notable companies include NATIONAL GRID ELECTRICITY TRANSMISSION PLC, SCOTTISH HYDRO ELECTRIC TRANSMISSION PLC, SP TRANSMISSION PLC.
Related SIC codes within the same division include: 35110 (Production of electricity), 35140 (Trade of electricity), 35300 (Steam and air conditioning supply), 35130 (Distribution of electricity). Companies may use multiple SIC codes if they operate across several of these related activities. When registering with Companies House, businesses should select the code that best represents their primary activity.
You can search for companies with SIC code 35120 (Transmission of electricity) using UVAGATRON's company explorer, which allows filtering by SIC code, location, and company status. Alternatively, Companies House offers a basic search on their website. Our platform adds risk intelligence, director networks, and signals from 50+ government databases to each company record.
Search, filter, and analyse 427 companies classified under this SIC code with AI-powered risk intelligence.
Data sourced from Companies House, HM Land Registry, FCA Register, and 50+ government databases. SIC classification follows the UK Standard Industrial Classification of Economic Activities 2007 (SIC 2007). Last updated: 2026-04-17.