Key takeaways
- The register covers limited companies, LLPs and some other entities across England and Wales, Scotland and Northern Ireland.
- SIC codes, registered office location, incorporation date and status are the most useful fields for prospecting.
- It does not include email addresses, phone numbers or, for most small companies, turnover and headcount.
- Treat the register as a reliable list of who exists and what they do, then add your own research.
What is on the Companies House register
Every UK limited company must register with Companies House and keep its details up to date. For each company the register holds the company name and number, company type, status (active, dissolved, in liquidation and so on), incorporation date, registered office address, SIC codes, officers, people with significant control and the history of filed documents such as accounts and confirmation statements.
The data is published under the Open Government Licence, which means it can be reused — including commercially — as long as the source is acknowledged.
The fields that matter for lead generation
For most agencies and service providers, four fields do most of the work.
- 01SIC codes: five-digit codes describing what a company does, such as 69201 accounting and auditing or 43910 roofing.
- 02Registered office location: a town, city or postcode that lets you build regional lists.
- 03Incorporation date: separates brand-new companies from established ones.
- 04Company status: lets you exclude companies that are dissolved, in liquidation or in administration.
How to search the register for leads
The Companies House website is designed for looking up individual companies. It has an advanced search, but working through results, opening each record and copying details into a spreadsheet is slow.
ClientFinch uses the official Companies House API behind a search built for prospecting. You combine a company name, up to five SIC codes, a location, an incorporation date range and a status, page through live results, open a full company profile, and save the companies that fit to a shortlist with private notes and CSV export.
Limitations to keep in mind
SIC codes are chosen by the company and are sometimes broad or out of date, so a company listed under 82990 (other business support activities) could do almost anything. Registered offices are often an accountant’s address rather than a trading location. Small companies can file micro-entity accounts that reveal very little about their size.
The register also does not hold marketing contact details. You will need to find the right person and channel yourself — usually via the company’s own website — and make sure your outreach complies with UK GDPR and PECR.
From search results to a shortlist
The goal is not the longest list, it is the most relevant one. Review each result, open the profile, check the company’s website, and only save companies where you can say in one sentence why you are getting in touch. Write that sentence in the lead’s notes. When you export to CSV, the notes travel with the list, so your outreach starts with context.
Try it: active roofing companies in Sheffield
Live data- SIC: 43910 Roofing activities
- Location: Sheffield
- Status: Active
Free account required — the first companies are free to explore.
This guide is general information, not legal advice. For data protection questions, see the ICO’s direct marketing guidance.