UK B2B Prospecting · 2026 Guide
SIC code lookup: how to find UK B2B companies by industry (free 2026 guide)
It's 9pm. You're three coffees in, trying to build a list of UK companies that actually match your ICP. You typed your industry into Sales Navigator and got 14,000 results, most of them American, most of them irrelevant. The fix isn't a £600/month tool. It's a 5-digit code that Companies House gives you for free.
5-minute summary
- SIC = Standard Industrial Classification. A free 5-digit code every UK limited company files at Companies House.
- ~730 codes total. Search them at Companies House Advanced Search by code + location + active status.
- LinkedIn's industry filter is too broad for UK SMBs. SIC is the cleanest route to a real list.
- 4 traps: 70229 catch-all consultancies, holding companies, dormant companies, SIC drift.
- Manual workflow: ICP → 2-4 SIC codes → Companies House filter → CSV → verify against websites. ~2 hours for a clean 50-company list.
What a SIC code actually is
SIC stands for Standard Industrial Classification. It's a 5-digit code maintained by the Office for National Statistics. Every UK limited company picks one (up to four) when they file at Companies House to describe what they actually do. They're free, public, machine-readable, and updated when the company files accounts.
The current list is SIC 2007, with ~730 codes grouped into 21 sections (A through U). Section M covers professional services. Section C covers manufacturing. Section J covers IT and information services. Within each section you drill down to 5-digit specificity.
They're not perfect. Companies self-report, ~50% of UK limited companies are dormant or non-trading, and the catch-all 70229 (management consultancy) hides 380,000 companies that aren't really consultancies. But for finding UK B2B firms by industry, nothing else is this clean and this free.
Why most B2B lists are broken
LinkedIn's industry filter is too coarse for UK SMBs
Two reasons LinkedIn's industry tag fails for UK B2B work:
- 1.Self-selected, often wrong. A 5-person UK accountancy firm sets up their LinkedIn page, picks 'Financial Services' from a dropdown in 2014, and never touches it again. Now they sit in a bucket with Barclays.
- 2.Aggressively bucketed. LinkedIn 'Financial Services' is the same tag for a sole-trader mortgage broker and a tier-1 investment bank. No size, no sub-niche, no recency.
SIC codes don't have either problem. They're filed against the legal entity, audited annually when accounts are filed, and the codes themselves are specific (69201 is auditing accountants. 69202 is bookkeepers. Those are two different buyers).
3 free ways to look up SIC codes
Companies House Advanced Search (the workhorse)
Filter all UK companies by SIC code + active status + registered office location + incorporation date. Paginated, max ~5,000 results per query, free. This is the route you actually use to build lists.
ONS SIC 2007 hierarchy (the dictionary)
The official list. Use it to find which code matches your ICP. Drill from section (A-U) → division (2-digit) → group (3-digit) → class (4-digit) → sub-class (5-digit). 'Accounting' sits at 69.20.1.
Companies House Bulk Download (the data dump)
Free monthly CSV of all ~5m UK active companies including SIC codes. ~3 GB unzipped. Filter locally with pandas/Excel. Use this when you need the full universe, not just the first 5,000.
SIC → LinkedIn industry translation
There's no official mapping. Here's the working one we use across UK B2B clients. Use SIC at the Companies House stage to build the named list, then use the LinkedIn industry column to set the broad filter when matched targeting fails.
| SIC Code | UK Description | Closest LinkedIn Industry |
|---|---|---|
| 69201 / 69202 | Accountants, auditors, bookkeepers | Accounting |
| 69101 / 69102 / 69109 | Solicitors, barristers, other legal | Law Practice / Legal Services |
| 70229 | Management consultants (the catch-all) | Management Consulting |
| 73110 / 73120 | Advertising agencies, media reps | Marketing & Advertising |
| 62012 | Business and domestic software development | Computer Software |
| 62020 / 62090 | IT consultancy and other IT services | Information Technology & Services |
| 64191 / 64929 | Banks, other credit granting | Banking / Financial Services |
| 66220 | Insurance brokers and agents | Insurance |
| 41100 / 41201 / 41202 | Construction of buildings | Construction |
| 28xxx / 29xxx | Manufacture of machinery, motor vehicles | Machinery / Automotive |
| 86xxx | Health, hospital, GP, dental | Hospital & Health Care |
| 46xxx | Wholesale trade (across categories) | Wholesale |
How many UK companies sit under common B2B SIC codes
Active UK limited companies (rounded), to help you sanity-check the pool size before you commit to a code. The 70229 catch-all dominates everything else, which is why you can't use it alone.
Active UK Ltd companies by SIC code
Approximate figures from Companies House active company data.
Figures rounded from Companies House active company snapshots. Use as order-of-magnitude indication, not precise count.
The 4 SIC traps that wreck B2B lists
1. Holding companies under 70100 / 64209
Hundreds of thousands of 'companies' that are just legal shells with no employees, no website, no buyers. Filter out 70100 ('activities of head offices') and 64209 ('activities of other holding companies') unless you specifically want PE/HoldCo targets.
2. Dormant or non-trading companies
Roughly half of all UK limited companies are dormant. Companies House Advanced Search → filter status to 'Active' only. Then cross-reference with accounts: no filing in 18 months = almost certainly dead.
3. SIC drift (the code is years out of date)
A 2014-incorporated SaaS company that started as 'web design' (62012) and pivoted to ecommerce platform never updated the code. The code says one thing, the website says another. Always verify against the website before you spend.
4. The 70229 catch-all
70229 'management consultancy other' is the lazy default. Real consultancies sit there, but so do 380,000 freelancers and shell companies. Never target 70229 alone. Pair it with employee count + revenue band + active accounts to thin the pool.
Worked example · 15 minutes
Building a 50-company UK accountancy list, manually
Say your ICP is: "UK chartered accountancy firms, 20-80 staff, serving owner-managed SMBs." Here's the 15-minute manual workflow.
- 1
Pick the right SIC codes
69201 (accounting and auditing) and 69202 (bookkeeping). Skip 69203 (tax consultancy) unless tax is the buyer.
- 2
Open Companies House Advanced Search
Paste 69201, 69202 into the SIC filter. Set status to Active. Set company type to Ltd.
- 3
Add a location filter
Filter by registered office postcode (e.g. London + Manchester + Birmingham). This kills the dormant Isle of Man shells.
- 4
Set incorporation date
Filter to companies incorporated more than 3 years ago. Filters out new sole-trader incorporations dressed as Ltds.
- 5
Export the first 200 results
Click through pages, copy to a CSV. Companies House caps at 5,000 results so order by 'recently filed' to get active ones.
- 6
Verify against websites
Open each in a new tab. Discard anyone whose website is a holding page, a freelancer's portfolio, or who clearly has under 20 staff. Aim for 50 verified survivors.
- 7
Layer with job titles
Add 8-15 titles (Managing Partner, Audit Partner, Tax Partner, Practice Manager, Head of Marketing) before any campaign goes live.
Total time: 90-120 minutes once you're practiced. Full accountancy lead-gen playbook here.
Or skip the spreadsheet
Get the same 50-company UK list in 12 seconds
The Account List Builder runs SIC + size + geography + active-status filters automatically. Returns 50 named UK companies plus boolean strings for LinkedIn and Apollo. Free. No catch.
Build my listFrequently asked questions
What is a SIC code?+
SIC stands for Standard Industrial Classification. It's a 5-digit code that every UK limited company self-selects when filing at Companies House to describe what they do. There are around 730 codes in the SIC 2007 list maintained by the ONS. They're free, public, and the closest thing the UK has to a clean industry filter.
How do I look up a company's SIC code for free?+
Three free routes. One: search the company on Companies House (find-and-update.company-information.service.gov.uk). The 'Nature of business (SIC)' line shows the codes. Two: use Companies House Advanced Search to filter all UK companies by SIC code, location, and size. Three: cross-reference codes against the ONS SIC 2007 hierarchy on ons.gov.uk for definitions.
Where can I find the full list of UK SIC codes?+
The Office for National Statistics publishes the SIC 2007 hierarchy at ons.gov.uk/methodology/classificationsandstandards. Companies House also keeps a working list of valid codes. There are ~730 codes grouped into 21 high-level sections (A-U).
How many SIC codes can a UK company have?+
Up to 4. Most firms only file one, and it's often the catch-all 70229 (management consultancy). That's why SIC alone is a starting filter, never a finishing one.
Why is SIC code 70229 so common?+
Because it's the lazy default. 70229 means 'management consultancy activities other than financial management'. It captures real consultancies, plus thousands of one-person service businesses who didn't know what else to pick. Around 380,000 UK companies sit under it. Treat it as a starting pool, not a target list.
Can I search Companies House by SIC code?+
Yes, through Companies House Advanced Search. You can filter by one or more SIC codes, by company status (active), by incorporation date, and by location (registered office postcode). It's slow, paginated, and limited to ~5,000 results per query, but it's free and accurate.
How do I map a SIC code to a LinkedIn industry?+
SIC and LinkedIn industries don't share a taxonomy, but they overlap in obvious places. SIC 69201 maps to LinkedIn 'Accounting'. 70229 maps to 'Management Consulting'. 62012 maps to 'Computer Software'. There's no official translation table, which is why we built one (see the mapping table above). Use SIC to build the named list, then use LinkedIn industry as the broad filter when matched targeting fails.
What's the difference between SIC and NAICS?+
SIC is the UK system. NAICS is the North American system. They're not interchangeable. If you're targeting UK companies, ignore NAICS. If you're targeting US/Canada, use NAICS through ZoomInfo / Apollo / Crunchbase.
Why are LinkedIn's industry filters bad for UK SMBs?+
Two reasons. One: LinkedIn industries are self-selected by the company page admin, often years ago, often wrong. Two: LinkedIn buckets aggressively. 'Financial Services' on LinkedIn covers everything from a 2-person mortgage broker to Barclays. SIC codes are more specific and update when the company files accounts.
Can I use SIC codes for B2B outreach in Apollo or Sales Navigator?+
Sales Navigator doesn't accept SIC codes directly. Apollo doesn't either. You use SIC at the Companies House layer to build the named list, then upload that named list as a Matched Audience (LinkedIn) or as a saved account list (Apollo). That's the proper workflow.
What are the 4 most common SIC code traps?+
One: holding companies coded 70100 or 64209 dominate results and aren't operating businesses. Two: dormant companies (50% of all UK limited companies are dormant or non-trading). Three: SIC drift, where a company picked a code at incorporation that no longer reflects what they do. Four: 70229 catch-all consultancies that aren't really consultancies.
How do I filter out dormant companies?+
On Companies House Advanced Search, filter to 'Active' status only. Better, cross-reference against filed accounts: companies that haven't filed accounts in 18 months are almost certainly dead.
Can I get a list of UK companies by SIC code in CSV format?+
Companies House offers a free monthly bulk download of all UK companies at download.companieshouse.gov.uk. It's a ~6m row CSV with SIC codes included. Filter it locally. Or, much faster, use the Account List Builder which already does the SIC + size + geography filtering.
Are SIC codes accurate?+
Roughly. Companies self-report and there's no audit. Expect 70-85% accuracy on the active company subset, lower for shell/holding companies. Cross-reference with the company's website before you spend any money targeting them.
What's the fastest way to build a UK target account list using SIC codes?+
Manually: write your ICP, pick 2-4 SIC codes that match, use Companies House Advanced Search with 'Active' + location + incorporation filters, export the first 200 results, then verify each against the company website. 2-4 hours for a clean 50-company list. Or use the free Account List Builder which does the same in 12 seconds.
Do SIC codes work for sole traders and partnerships?+
No. SIC codes only apply to UK limited companies (Ltd) and LLPs registered at Companies House. Sole traders and ordinary partnerships are invisible to this approach. For those you need a different sourcing route (industry directories, trade bodies, LinkedIn directly).
Or do what you do best
SIC codes get you the list. Layered titles, sharp creative and weekly iteration get you the meetings.
We run this exact stack for 30+ niche UK B2B firms. Let us run yours while you go run your business.
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