Architectural and engineering activities; technical testing and analysis (SIC division 71)
Division 71 of the UK SIC 2007 list. It holds 6 codes, listed in full below with the number of active UK companies filed under each.
What sits in division 71
Architects, engineers and technical testing labs share this division. Engineering leads on numbers. Code 71129 holds general engineering activities. Code 71122 covers scientific and technical consulting. Code 71121 covers design work for industrial process and production. Architecture splits in two: 71111 for architectural practices and 71112 for urban planning and landscape work. Code 71200 marks testing and analysis houses, from materials labs to environmental testing. Many entries are chartered professionals in small limited companies. Established multidisciplinary firms sit alongside them.
Construction supply chains drive most of the selling here. Main contractors and developers search these codes to find design partners. Software vendors sell CAD, BIM and project tools. Insurers push professional indemnity, which every practice has to carry. Recruiters work the engineering codes hard, because demand for chartered engineers beats supply. A new incorporation often means a senior engineer or architect has left a big practice with clients in tow. Steady filings plus visible growth mark the firms winning places on frameworks.
How to read a division 71 code
A UK SIC code is five digits and division 71 is the first two of them. Everything filed under 71 shares those digits: all 6 codes below begin 71, then the third digit narrows to a group, the fourth to a class and the fifth to the subclass a company actually picks. Division 71 sits inside section M, professional, scientific and technical activities, which is the broadest tier of the classification. So a code is read left to right, from an industry down to a specific activity.
More on how division 71 codes are built
Companies choose their own codes at incorporation and can change them on any confirmation statement, and Companies House does not check the answer. A company may list up to four. That is worth knowing before you treat any division total as a headcount: the numbers here are what companies said about themselves, on the August 2026 register, and the largest single code in this division is 71129, other engineering activities.
Working division 71 as a list
Division 71 holds 6 codes and 117,068 active companies between them. 71129 is the largest at 32 per cent and the top three take 79 per cent, with the rest spread across the remaining 3 codes. That is balanced enough that the division is a reasonable unit to work, though the leading code alone will usually give you a cleaner list.
More on working division 71
A caveat that matters more in some divisions than others: a company may register up to four SIC codes, and the figures below count every position, not just the first. A business filed under two codes in this division appears under both. Treat the totals as reach rather than a headcount, and if you need a clean list, filter to companies whose FIRST code sits in the division. Every company you pull carries the Companies House record, the director's name, a verified website and a verified email, and the ones we cannot complete are not charged.
Every SIC code in division 71
71111, Architectural activities71112, Urban planning and landscape architectural activities71121, Engineering design activities for industrial process and production71122, Engineering related scientific and technical consulting activities71129, Other engineering activities71200, Technical testing and analysisProspecting this division
Division 71 companies, as leads
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Division 71 questions
Should an architect use SIC code 71111 or a construction code?
A design practice belongs under 71111, or 71112 for planning and landscape work. Division 41 and 43 codes describe businesses that physically build. Companies House does not police the choice. One thing does matter: the title architect is legally protected in the UK by the Architects Registration Board. Only ARB-registered individuals may use it, whatever SIC code the company holds.
Which SIC code fits a consulting engineer?
Most consulting engineers pick 71122 for scientific and technical consulting. Code 71121 suits industrial and production design. The broader 71129 works when neither is a clean fit. The choice is yours. Codes are self-declared at incorporation and amendable on any confirmation statement (CS01). A company can carry up to 4, so many practices pair an engineering code with a project management or testing code.
Find companies across division 71
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