UK SIC 2007 · 71129
Other engineering activities
Other engineering activities is UK SIC code 71129, part of division 71 (Architectural and engineering activities; technical testing and analysis) in the SIC 2007 classification. As of the July 2026 Companies House register, 37,797 active UK companies list 71129 among their SIC codes, and 26,857 list it as their first code. That makes it the most used code in its division.
As of the July 2026 Companies House register, 37,797 active UK companies list 71129 among their SIC codes (26,857 as their first code).
Companies House data refreshed daily. Page reviewed July 2026.
Division 71: Architectural and engineering activities; technical testing and analysis
Architectural and engineering practices share this division with technical testing labs. Engineering leads the numbers: 71129 holds general engineering activities, 71122 the scientific and technical consulting side, and 71121 design work for industrial process and production. Architecture splits between 71111 for architectural practices and 71112 for urban planning and landscape work, while 71200 identifies testing and analysis houses, from materials labs to environmental testing. Many entries are chartered professionals trading through small limited companies alongside established multidisciplinary firms.
Construction supply chains drive most of the prospecting here. Main contractors and developers search these codes for design partners, while software vendors sell CAD, BIM and project tools, and insurers push professional indemnity, which every practice must carry. Recruiters target the engineering codes hard because demand for chartered engineers outstrips supply. New incorporations often mean a senior engineer or architect leaving a big practice with clients in tow, and steady filings plus visible growth mark firms winning framework places.
Related SIC codes
71122, Engineering related scientific and technical consulting activities71111, Architectural activities71121, Engineering design activities for industrial process and production71200, Technical testing and analysis71112, Urban planning and landscape architectural activitiesWho uses this code in B2B outreach
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Where SIC 71129 clusters in the UK
About SIC 71129
How many UK companies use SIC code 71129?
37,797 active UK companies include 71129 (Other engineering activities) among their up-to-four registered SIC codes, of which 26,857 list it first. Figures are from the July 2026 Companies House register snapshot, counting active companies only.
Should an architect use SIC code 71111 or a construction code?
A design practice belongs under 71111 (or 71112 for planning and landscape work), while division 41 and 43 codes describe businesses that physically build. Companies House does not police the choice, but note that the title architect is legally protected in the UK by the Architects Registration Board, so only ARB-registered individuals may use it, regardless of what SIC code the company holds.
Which SIC code fits a consulting engineer?
Most consulting engineers choose 71122 for scientific and technical consulting, 71121 for industrial and production design, or the broader 71129 when neither is a clean fit. The choice is yours: codes are self-declared at incorporation, amendable on any confirmation statement (CS01), and a company can carry up to 4, so many practices pair an engineering code with a project management or testing code.
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