Email marketing means sending useful, regular emails to people who’ve agreed to hear from you, so they remember you and come back when they’re ready to buy. For a small business it’s one of the cheapest and most reliable channels there is, because your list belongs to you. No algorithm decides who sees your post, and no platform can take your audience away.
If your email list is currently a spreadsheet of past customers you’ve never quite got round to emailing, this guide is for you. We’ll cover the rules (they’re simpler than you think), how to grow a list, what to actually send, and how to make sure it lands in the inbox.
The short version
- UK marketers have reported a return of over £42 for every £1 spent on email (DMA, 2019).
- Under UK law (PECR), you need consent to email individuals, with one important exception: the soft opt-in for your existing customers.
- Grow your list with something genuinely useful in return for an email address, such as a guide, a checklist or a free tool.
- One helpful email a month beats a weekly sales pitch.
- If you ever send in bulk, Gmail, Yahoo and Microsoft now require SPF, DKIM and DMARC on your domain, and Gmail wants spam complaints kept below 0.3%.
In this article
Why email still works
Every other channel is rented. Google can change its results, Facebook can show your posts to fewer people, and an AI assistant might not mention you this month. Your email list is different: if someone has asked to hear from you, you can reach them whenever you like.
It also works with how people buy. Most of your future customers aren’t ready today. A friendly email every month keeps your name in front of them, so when the boiler breaks or the year-end accounts loom, you’re the one they think of.
The rules: PECR and UK GDPR in plain English
Marketing emails in the UK are covered by the Privacy and Electronic Communications Regulations (PECR), alongside UK GDPR. The Information Commissioner’s Office (ICO) enforces both. This is a summary, not legal advice, so check the ICO’s guidance for anything unusual.
Emailing individuals (and sole traders)
You need their consent: a clear, unticked opt-in where they actively agree to receive your marketing emails. Keep a record of when and how they agreed.
The soft opt-in for existing customers
You can email your own customers without separate consent if all of these are true:
- you got their email address when they bought from you, or while discussing a purchase;
- you’re only marketing your own similar products or services;
- you gave them a simple way to say no when you collected their details; and
- every email you send includes an easy way to unsubscribe.
The Data (Use and Access) Act 2025 added a similar soft opt-in for charities promoting their charitable purposes, and the ICO published guidance on it in April 2026.
Emailing businesses
Emails to limited companies, LLPs and public bodies (what the law calls “corporate subscribers”) don’t need consent under PECR, but you must say who you are and give a working way to opt out. Sole traders and some partnerships count as individuals, so the consent rules apply to them. If you’re emailing a named person at a company, UK GDPR still applies to their data.
Every email, every time
- Say clearly who it’s from.
- Include a working unsubscribe link, and act on it promptly.
- Don’t buy email lists. You can’t prove consent, and they wreck your deliverability.
How to grow your list
- Ask existing customers. Add a tickbox to your quote form, booking system or checkout, worded clearly: “Send me one useful email a month. Unsubscribe any time.”
- Offer a lead magnet. Something genuinely useful in return for an email: a price guide, a seasonal checklist, a short video course or a free tool. Our own marketing ideas tool works this way: visitors see six ideas straight away and can ask for the full plan by email.
- Put a sign-up form where people are already reading. At the end of your most popular blog posts and on your contact page, not in a pop-up that appears after two seconds.
- Collect sign-ups in person. At events, in your shop or after a consultation, with a simple form that records consent.
- Make it easy to share. A line at the bottom of each email: “Know someone who’d find this useful? Forward it on.”
Quality beats quantity. Five hundred local customers who chose to hear from you are worth far more than ten thousand strangers.
What to send
Think of each email as a small favour, not an advert. A simple monthly format that works for most small businesses:
- One useful thing: a tip, a short how-to or an answer to a question customers keep asking.
- One piece of proof: a recent job, a review or a short case study.
- One gentle offer or next step: book your annual service, try the new menu, reply with a question.
Some ideas by sector:
| Business | Useful email ideas |
|---|---|
| Trades | Seasonal maintenance checklists, “what we found this month”, price guides |
| Salons and clinics | Aftercare tips, rebooking reminders, new treatments |
| Accountants and solicitors | Deadline reminders, rule changes explained simply, client stories |
| Cafés and shops | New stock or menus, events, loyalty rewards |
| B2B services | Short guides, case studies with numbers, invitations to webinars |
Also set up a short welcome email for new subscribers. It’s usually the most-read email you’ll ever send, so say hello, deliver what you promised and tell them what to expect.
Getting into the inbox, not the spam folder
Deliverability sounds technical, but most of it comes down to a few settings and good habits.
- Send from your own domain ([email protected]), not a free Gmail or Hotmail address.
- Set up SPF, DKIM and DMARC on your domain. These are records that prove your emails really come from you. Since February 2024, Gmail and Yahoo have required all three from anyone sending 5,000 or more emails a day to their users, and Microsoft followed for Outlook and Hotmail in May 2025. Gmail stepped up enforcement in November 2025. Even if you send far less, they help your emails land.
- Use a proper email platform such as Mailchimp, Brevo or MailerLite rather than BCC from your inbox. They handle unsubscribes, the one-click unsubscribe header Gmail asks bulk senders for, and the technical bits.
- Keep complaints low. Gmail asks senders to keep spam reports below 0.1% and never let them reach 0.3%. The fastest way to stay safe is to only email people who want to hear from you.
- Clean your list. Remove addresses that bounce, and people who haven’t opened anything in a year (after one “do you still want these?” email).
The numbers to watch
| Measure | What it tells you | Watch out for |
|---|---|---|
| Clicks | Whether people found the email useful enough to act | The most reliable engagement number |
| Replies and enquiries | Whether email is bringing in work | The one that matters most |
| Unsubscribes | Whether you’re sending too often or off-topic | A spike after a particular email |
| Bounces and spam complaints | The health of your list | Anything creeping up |
| Opens | A rough guide at best | Apple Mail Privacy Protection inflates open rates, so don’t rely on them |
Track enquiries from email in Google Analytics 4 by adding UTM tags to your links (most email platforms do this for you).
Your questions, answered
How often should a small business send marketing emails?
Once a month is a good place to start for most small businesses. It’s often enough to stay remembered and rare enough that every email can be genuinely useful. Retailers with frequent offers may send weekly.
Can I email my existing customers without asking first?
Usually, yes, under the soft opt-in: if you got their email during a sale or a conversation about a sale, you only market your own similar products or services, you gave them a chance to opt out when you collected their details, and every email lets them unsubscribe.
Is it legal to buy an email list in the UK?
For individuals, it’s almost never compliant, because you can’t show that each person consented to hear from you specifically. It also damages your sender reputation. Grow your own list instead.
What’s a good open rate for a small business email?
Open rates have become unreliable since Apple’s Mail Privacy Protection started loading emails automatically in 2021, which makes opens look higher than they are. Focus on clicks, replies and enquiries instead.
Which email platform should I use?
Any of the well-known ones (Mailchimp, Brevo, MailerLite, Klaviyo for online shops) will do the job. Choose one that’s easy for you to use, connects to your website forms, and handles unsubscribes and sender authentication properly.
Ready for some help?
Want help setting up a welcome email, a lead magnet or a simple monthly newsletter that brings in work? Book a free chat. For more quick wins, try our free marketing ideas tool, or read 25 marketing ideas for small businesses.
References
- DMA, Marketer Email Tracker 2019.
- ICO, Guidance on direct marketing using electronic mail, updated 28 April 2026.
- ICO, The charitable purposes soft opt-in.
- Google, Email sender guidelines FAQ.
- Resend, Microsoft’s bulk sending requirements for 2025.