Where UK B2B data actually comes from

UK B2B prospect data comes from four places: the public record (mainly Companies House), professional networks (LinkedIn and Sales Navigator), commercial contact databases, and enrichment tools that find and attach contact details. No single source produces a usable list on its own; every decent database is an assembly of at least two of them. The order of assembly — companies first, people second, email addresses last — matters more than which tools you pick.

Why does the source matter more than the tool?

Because targeting sets the ceiling on everything downstream. Good copy cannot save bad targeting: if the list is wrong, the campaign is wrong, and no subject line fixes it. Most firms shop for a sending tool first and ask where its data comes from never. Reverse that. Once you understand the four sources and what each is actually good at, tool choice becomes a detail. The full assembly process, from ICP definition to verified list, is laid out in The B2B Database Building Guide; this article covers the raw material.

What does the public record give you?

Companies House holds a record for every limited company in the UK — name, registered address, incorporation date, SIC codes, filing history and named officers — and it is free, including the API. Filed accounts give you a rough size band: micro-entity, small, medium. That makes it the best starting point for the company half of a UK list. It is complete, it is current within filing deadlines, and nobody can opt out of it.

What it does not hold: email addresses, phone numbers, or reliable industry labels. SIC codes are self-reported and frequently wrong, stale or generic. Treat the register as a census, not a contact list. The practical filters are written up in Companies House as a prospecting database.

What do LinkedIn and Sales Navigator add?

People. Companies House tells you a firm exists and names its directors; LinkedIn tells you who actually runs marketing, operations or sales there today. Sales Navigator adds the filters that matter — headcount, geography, function, seniority — and keeps the picture roughly current, because people update their own profiles when they move jobs. Note "roughly": titles are self-described, headcounts are self-reported, and dormant profiles linger for years. Getting the data out cleanly is its own job, covered in Sales Navigator: extracting a clean list.

Where do commercial databases fit?

Providers such as Apollo, Cognism and ZoomInfo aggregate the above and attach contact details at scale. They are genuinely useful as accelerators — one query can do what would otherwise take a day of manual assembly. Two cautions apply. First, coverage of UK firms in the 5–50 staff range is patchier than the marketing suggests; these products are typically strongest on larger, US-centric companies. Second, every record starts decaying the moment it is collected, and commonly faster than the vendor refreshes it. A commercial database is a source to draw from, not a list to send to — which is also the short version of why bought lists lose to built lists.

How do four sources become one list?

The mechanism, step by step:

1. Define the ICP, then pull the company shortlist. Companies House or a commercial database, firmographics only at this stage.
2. When you have companies, find the people. Use Sales Navigator to identify the decision-maker at each firm. One name per company.
3. When you have people, find the addresses. Run enrichment — cheap sources first, paid lookups only for the gaps.
4. When you have addresses, verify every one. No record reaches the sending tool unverified, because a few bad addresses damage deliverability for the whole mailbox.

This is the same pipeline behind our £950 standalone database build, and the order never changes: companies, people, addresses, verification.

Which sources should you treat with suspicion?

Anything without a provenance trail. Bought lists of unknown origin, scraped directories, "opt-in" databases that cannot say where the opt-in happened — these fail on accuracy first and compliance second. UK law does permit B2B cold email to corporate subscribers under PECR, with identification and an opt-out, but you still need to know where your data came from and why you hold it (that is a summary, not legal advice).

The broader point: choosing sources is a decision you should make once. Write the stack down — public record for companies, network for people, enrichment for addresses, verifier at the gate — and stop re-litigating it every campaign. It is the same logic as pre-deciding your way out of overwhelm: a decision is only expensive if you keep re-making it.

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Next step: the Growth System Audit — £450, seven days, credited against any build — maps where your growth system leaks and what to build first.