UK outbound is governed by PECR alongside UK GDPR, and PECR draws a line that most sending tools ignore: the rules for unsolicited marketing email depend on whether the recipient is a corporate subscriber or an individual subscriber.
The distinction
A corporate subscriber is a limited company, an LLP, or a public body. Unsolicited marketing email to a named person at one of these can generally be sent under legitimate interests, provided the message is relevant to their role, you identify yourself, and you offer a working opt-out.
An individual subscriber is a sole trader or an unincorporated partnership. Legally these are treated as individuals, and the consent requirement is materially stricter. The soft opt-in exemption relates to your own customers, which a cold prospect by definition is not.
The trap
sam@samsplumbing.co.uk may be a limited company or a sole trader. The email address does not tell you, the website usually does not tell you either, and no enrichment provider reliably classifies it. A tool that assumes corporate for everything with a business-looking domain is sending unlawfully to an unknown share of every UK list.
Why unknown has to block
The honest engineering answer is that this cannot be inferred, so it must be declared. When a contact's subscriber class cannot be established, the correct behaviour is to refuse the send rather than guess. A guess here is not a product decision, it is a regulatory one being made silently on the operator's behalf.
This is why contacts imported from an enrichment provider arrive classified as unknown in BriefWork, and why unknown is blocked rather than sendable. The visible cost is that your sendable count is lower than the number your provider returned. That gap is the part other tools hide.
What every UK cold email needs regardless
- A lawful basis recorded at import, not reconstructed later
- Clear identification of the sender, including a registered company name
- A postal address where required
- A working one-click opt-out that takes effect immediately
- Suppression that survives across every campaign, not just the one they replied to
Suppression is where automated sending most often fails an audit. An unsubscribe recorded against one campaign, while the address remains sendable in another, is not an opt-out. Suppression has to be a property of the workspace.
This article describes how the rules are implemented in a product and is not legal advice. If you are sending at volume into the UK, have a solicitor review your process.