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Guide

What Is Opt-in Data? Consent, Third Parties and Proof Explained

Opt-in data is contact data from people who actively agreed to receive marketing — rather than being added without being asked. With bought data, they usually agreed to hear from third-party companies when they signed up somewhere else.

What makes consent valid

Under UK GDPR, consent has to be freely given, specific, informed and unambiguous — an active tick, not a pre-ticked box. The person should know what kind of companies may contact them and how.

Third-party (indirect) consent

When consent is collected by one company for marketing by others, it has to be specific enough to cover the company that uses it. For texts, emails and automated calls this matters most, so check the consent wording and keep the record of when, where and how the person agreed.

The proof to look for

  • The date and time they opted in.
  • The website (URL) where they signed up.
  • The channels they agreed to — call, SMS, email, post.

Every DataMembership record includes all three.

Questions

Does opt-in data still need TPS screening?

For calls, yes — screen against TPS/CTPS. We do it before delivery.

This guide is general information, not legal advice. For the full rules see the Information Commissioner's Office (ico.org.uk). Last updated October 2026.