UK Business DirectoryHow to find companies in the UK for B2B prospecting
Companies House confirms who exists. Google Maps shows who actually trades. Here are 5 ways to build a UK company list by sector and city, and stay UK GDPR compliant while you sell.
Find Business··6 min read
Key takeaways
Companies House is the official register: free, authoritative, but no emails and no sole traders
There are around 2.7 million businesses on the UK business register, concentrated in London but spread everywhere
Combine sources: register for legal data, Google Maps for live trading firms, a business finder for verified contacts
UK GDPR allows B2B email to corporate addresses under legitimate interest, with relevance and opt-out
Definition
What is a UK business directory?
A UK business directory is a database of companies registered or trading in the United Kingdom, used by B2B teams to find and contact prospects by sector and location. The strongest directories combine the official Companies House register with live trading data, so each record carries name, registered address, sector, phone, website and a verified email.
The market behind that directory is large and uneven. The Office for National Statistics UK business register counts roughly 2.7 million businesses, while Companies House holds more than 5 million companies on its register, since one register tracks incorporated companies and the other tracks active enterprises. Most of them are small firms, exactly the long tail where the United Kingdom economy meets B2B sales.
Demand confirms it: according to Vonsel internal data (2026), restaurants and dentists are the most-prospected categories among paying teams, with London among the top cities worldwide alongside Madrid, New York and São Paulo. If you sell into the UK, you need more than a static list, you need a way to find businesses in any country worldwide and filter them down to your exact sector and city.
2.7M
businesses on the UK business register (ONS)
5M+
companies on the Companies House register (gov.uk)
120+
countries of verified businesses in Vonsel, UK included (internal data, 2026)
The methods
5 ways to find companies in the UK
There are five realistic routes to a UK company list. They differ in coverage, freshness and how much contact data you actually get:
1
Search Companies House (the official register)
The free Get information about a company service confirms legal name, company number, registered office, SIC code and filing status. It is the truth on who exists, but it carries no emails and excludes sole traders.
2
Browse online business directories
Trade directories and Yell style listings group companies by sector and town. Useful for discovery, but coverage is patchy, records age fast, and contact details are often missing or out of date.
3
Mine Google Maps by category and city
Search "accountants in Manchester" or "estate agents in London" to get live trading businesses with phone, website, opening hours and reviews. This catches sole traders and high street firms the register misses, but extracting it by hand is slow.
4
Cross reference into a clean list
Match register data against map data so each prospect carries both legal identity and live contact details. This is the same logic behind any solid business directory, structured records you can actually filter and segment.
5
Generate the list on demand from live data
A business finder searches live map and web data for "sector + UK city", returning name, address, phone, website, Google rating and a verified email in minutes. This is how modern teams build a business database without scraping or buying recycled records.
Build your UK company list in minutes
Search any UK city and sector, get verified emails, phones and Google ratings for every company, fresh live data, not a recycled directory dump.
Companies House vs directories vs a business finder
Source
What it gives you
What it misses
Companies House
Legal name, number, registered address, SIC code, filings, free
No emails, no sole traders, no live trading status
Online directories
Sector grouping, some phones and websites
Patchy coverage, ageing records, few verified emails
Google Maps
Live trading firms, phone, reviews, location
Slow to extract, no exportable emails by default
Business finder
Sector plus city, verified email, phone, rating, location
Paid tool, but cheapest per usable contact
Context is what turns a record into a conversation. HubSpot's sales statistics show that most buyers prefer email as their first sales touchpoint, and that reps lose roughly a fifth of their day to writing those emails. A directory that already includes each company's reviews and sector lets you personalize in seconds instead of researching for minutes.
A UK directory is only as good as its freshness. Companies close, rebrand and move every week, and a register record without a verified email is a name, not a lead. Pairing official identity with live trading data is the whole game.
Compliance & mistakes
UK GDPR rules and the 4 mistakes that kill UK campaigns
UK data protection follows the GDPR framework, retained as UK GDPR alongside PECR. B2B email to corporate addresses can rely on legitimate interest, but the ICO direct marketing guidance sets the bar. Here is the short version:
Email corporate mailboxes, and remember sole traders and partnerships need PECR style consent.
Make the offer genuinely relevant to that company's business.
Identify yourself and your company clearly in every email.
Include a one-click opt-out and honour it immediately.
Keep records of your lawful basis and delete data on request.
Mistake 1: trusting register data alone
A registered address is not a sales contact. Without a verified email and live trading status, you are emailing accountants and dormant shells, not buyers.
Mistake 2: ignoring sole trader rules
Sole traders and partnerships are treated more like individuals under PECR. Blasting them like limited companies is a compliance risk, not a shortcut.
Mistake 3: skipping verification
Sending to unverified addresses spikes bounces and blacklists your domain. Verify every email, syntax, domain, SMTP, before the first send.
Mistake 4: one national blast
A London fintech and a Sheffield workshop have different budgets and pains. Segment by sector, size and city before writing a single email.
A UK business directory is not a file you download once. It is a pipeline you keep fresh, verified and segmented by sector and city.
How Vonsel helps
How Vonsel builds your UK company list for you
Vonsel's Business Finder searches millions of verified businesses across 120+ countries, the UK included. Type a sector plus any UK city, "law firms in Leeds" or "marketing agencies in London", and get every company with name, address, phone, website, Google rating and email, 85-95% email accuracy and 90%+ phone accuracy, GDPR compliant on EU servers. Smart Reviews then summarizes each company's Google reviews with AI, so you know which firms struggle before you write a word. Plans on the pricing page start at €17.99/month, and you get 20 verified leads when you start the free plan.
In short:
Use Companies House for legal identity, then layer live trading and contact data on top.
Filter by sector and city, London, Manchester, Birmingham, instead of one national dump.
Stay UK GDPR compliant: corporate mailboxes, relevance, identification, opt-out.
Your UK company list, verified and ready today
Search any UK city and sector, export verified emails and phones for every company, and let AI summarize their reviews for instant personalization. See plans.
A UK business directory is a database of companies registered or trading in the United Kingdom, usually including company name, registered address, sector, phone, website and sometimes email. B2B teams use it to find and contact prospects by industry and location.
Is Companies House the best UK business directory?
Companies House is the official register of every limited company in the UK and is free to search, so it is the most authoritative source for legal name, company number and registered address. It does not include emails or sole traders, so most teams pair it with directories or a business finder for contact data.
How do I find companies in the UK by sector?
Filter Companies House by SIC code, browse a trade directory by category, or search Google Maps for a category plus a city such as law firms in Leeds. A business finder lets you combine sector and city in one query and returns verified contact details.
Can I get UK company emails legally?
Yes. Business contact data is widely available, and B2B email to corporate addresses is allowed under UK GDPR using legitimate interest. You must keep the offer relevant, identify yourself and honour opt-outs. Marketing to sole traders and partnerships triggers stricter PECR consent rules.
How many businesses are there in the UK?
The Office for National Statistics counts roughly 2.7 million businesses on its UK business register, concentrated in London and the South East but spread across every region. The vast majority are small firms, which is exactly the long tail B2B teams prospect.
What is the best free UK business directory?
Companies House is the best free official register, and Google Maps is the best free source of live trading businesses with phone numbers and reviews. Free sources rarely include verified emails, so teams that prospect at scale add a business finder on top.
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