Can you text or email past customers? The UK rules in plain English

Your past customers are the easiest people to win work from. They already know you, and many of them will need you again: another boiler service, the next MOT, the gutters before winter. The rules on texting and emailing them are simpler than most people think, but they are strict about a few things. This guide covers the rules for marketing by text and email in the UK, set by the Privacy and Electronic Communications Regulations (PECR) and enforced by the Information Commissioner's Office (ICO).

Is it a service message or marketing?

The first question is whether your message counts as marketing at all. A genuine service message, sent only to deal with something the customer has already arranged, is not marketing and does not need consent. The moment a message promotes something, the whole message counts as marketing.

Most reminders that ask people to book again sit on the marketing side. That is fine: it just means they need to meet the rules below.

The soft opt-in, explained

Normally you need someone's consent before sending them marketing texts or emails. The “soft opt-in” in regulation 22 of PECR is an exception for your own customers. You can rely on it when all four of these are true:

1. You got their contact details yourself, while selling to them or while they were asking about buying, such as a quote.
2. The message is about your own products or services, and similar to what they bought or asked about.
3. When you took their details, you gave them a simple way to refuse marketing.
4. Every message since gives them a simple, free way to opt out.

If any one of these is missing, you need consent. The rules above apply to individuals, which includes sole traders and most partnerships. Limited companies and LLPs are treated differently: you can send them marketing emails and texts without consent, as long as you say who you are and offer an opt-out.

What every marketing message needs

• Your business name, so they know who it is from.
• A free, simple opt-out, such as “Reply STOP to opt out” on a text or an unsubscribe link on an email.
• Opt-outs acted on, straight away, and recorded so the person is never added back by mistake.

A short, personal message works better anyway. For example: “Hi Sarah, it's Dave from Smith Heating. Your boiler service is due next month. Want me to book you in? You can pick a time here: [link]. Reply STOP to opt out.”

Set it up properly for future customers

The most common gap is condition three: nobody offered an opt-out when the details were taken. Fix it once and every future customer is covered. Add a line wherever you collect details, such as your quote form, booking form or job sheet:

Keep a note of who opted out, and when. If you use a job management or accounts system, there is usually a field for it.

Phone calls and post

Different rules apply. Before making marketing calls, check numbers against the Telephone Preference Service (TPS), unless the person has told you they are happy to be called by you. Marketing by post is covered by UK GDPR rather than PECR, and you must stop if someone asks.

What happens if you get it wrong

Most problems start with a complaint to the ICO. The ICO can order you to stop and can issue fines: in 2019 it fined EE £100,000 for sending marketing texts to customers who had opted out. The Data (Use and Access) Act 2025 has since strengthened the ICO's powers to enforce these rules. For a small business, the bigger cost is usually reputation: a customer who feels spammed is unlikely to book again.

This guide is a plain-English summary, not legal advice. For anything unusual, check the ICO's guidance or speak to a solicitor.