Other engineering activities (SIC code 71129)
Other engineering activities is UK SIC code 71129. It sits in division 71 (Architectural and engineering activities; technical testing and analysis) of the SIC 2007 list. On the August 2026 Companies House register, 37,759 active UK companies list 71129 among their SIC codes. 26,674 of them list it first. That makes it the most used code in its division.
37,759active UK companies list SIC 71129 among their codes on the public recordCompanies House · counts as of August 2026
SIC 71129 in numbers
37,759 companies is 0.73 per cent of the 5,190,464 active companies on the UK register. 71129 is the most used of the 6 codes we track in division 71.
26,674 put 71129 first and 11,085, 29 per cent, list it in one of their other three slots. First code only gives the tighter list; any position gives more of them.
ACTIVE COMPANIES BY REGISTERED-OFFICE POST TOWN (WHERE THE PAPERWORK SITS, NOT NECESSARILY THE WORK) · COMPANIES HOUSE PUBLIC RECORD, AUGUST 2026
London is the largest cluster at 14 per cent and the top five post towns hold 19 per cent, so the other 81 per cent sit across the rest of the country. A regional filter narrows the list without gutting it.
A worked example: 71129, registered office in London, incorporated in the last ninety days, from a pool of 37,759. Each lead you get arrives with a working website and a real email, and the director's name when the record has one. If we cannot complete one, you pay nothing.
SIC 71129 companies, as leads
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Architects, engineers and technical testing labs share this division.
Related SIC codes
How to read SIC 71129
SIC 71129 reads as division 71 (architectural and engineering activities; technical testing and analysis), group 711, class 7112, then the full five digits, inside section M, professional, scientific and technical activities. A company picks its own codes, up to four, and Companies House does not check them, so 71129 is the company's own description of what it does, and 26,674 list it first where 37,759 list it anywhere.
Who sells into division 71
Construction supply chains drive most of the selling here. Main contractors and developers search these codes to find design partners.
About SIC 71129
How many UK companies use SIC code 71129?
37,759 active UK companies list 71129 (Other engineering activities) among their registered SIC codes. Each company may register up to four. Of those, 26,674 put it first. The figures come from the August 2026 Companies House register snapshot, and count 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. 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.
Find UK SIC 71129 companies
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