Growing a UK E-commerce Business in 2026: Unit Economics, Reviews and the Rules
Online sales made up 28.8% of UK retail in September 2026 and were 6.8% higher than a year earlier. Here is a practical checklist for growing an online shop, including the CMA's tougher stance on fake reviews.
By Entrepreneur Group · Published · Updated
Editor's note: updated on 27 October 2026 with the latest ONS online sales data and CMA enforcement. An earlier version described a founder and company we could not verify; that case study has been removed.
Online shopping is a large and still-growing part of UK retail. In September 2026, 28.8% of retail sales were made online, and online spending was 6.8% higher than a year earlier, according to the Office for National Statistics. Over July to September, online spending was 7.4% higher than in the same quarter of 2025.
Growth is not guaranteed for any one shop, though. The ONS reported that online clothing retailers struggled in September because unseasonably warm weather hit sales of autumn and winter ranges. The businesses that grow are usually the ones that know their margins, keep customers coming back and stay on the right side of consumer law.
Start with the product and the customer
Before you spend heavily on advertising, be clear about:
- the problem you solve and who has it;
- evidence of quality, such as repeat orders, returns data and customer feedback;
- fulfilment needs, including storage, packaging and delivery times;
- seasonality, since weather and events can move demand sharply, as September showed.
Test with a small range and a clear way to collect feedback. An early sell-out is encouraging, but it is not proof that the business can scale.
Know your unit economics
This section is editorial guidance.
Track these numbers for each product or range:
- Contribution margin: the selling price minus product cost, packaging, payment fees, delivery and the expected cost of returns.
- Customer acquisition cost: total marketing spend divided by new customers won.
- Repeat rate: the share of customers who buy again within a set period.
- Return rate: high returns can wipe out the margin on a product.
- Stock cover: how many weeks of sales your stock covers, so you neither run out nor tie up too much cash.
Marketing can scale a product that works. It cannot fix a weak product, unclear positioning or unreliable delivery.
Reviews: the rules have teeth
Customer reviews are one of the most powerful tools in e-commerce, and the regulator is watching closely. Under the Digital Markets, Competition and Consumers Act, fake reviews are banned and the Competition and Markets Authority can fine businesses directly, up to 10% of global turnover.
In 2026 the CMA opened its first investigations into possible fake or misleading reviews, involving Autotrader, Feefo, Pasta Evangelists, Just Eat and Dignity, as Herbert Smith Freehills Kramer reported. The CMA stresses that no wrongdoing should be assumed. It also reviewed more than 100 business websites and sent 54 letters about missing review policies.
Businesses that publish reviews are expected to:
- publish a policy that bans fake reviews and explains how incentivised reviews are handled;
- take reasonable steps to prevent, detect and remove fake reviews;
- not hide negative reviews or present ratings in a misleading way;
- clearly disclose any incentive given for a review, such as a discount.
Build trust without exaggeration
- Describe products accurately, with honest images and sizing.
- Show delivery and returns information clearly before checkout, including all fees.
- Respond quickly to customer questions and complaints.
- Handle customer data lawfully and only send marketing to people who have agreed to receive it.
- Avoid fake urgency, such as countdown timers that reset or false "only two left" messages.
Frequently asked questions
What percentage of UK retail sales are online?
28.8% of UK retail sales were made online in September 2026, according to the ONS, down slightly from 28.9% in August.
Are fake reviews illegal in the UK?
Yes. Fake reviews are banned under the Digital Markets, Competition and Consumers Act, and the CMA can fine businesses up to 10% of global turnover.
What should an online shop measure first?
Start with contribution margin per product after all costs, including delivery and returns, then customer acquisition cost and repeat purchase rate.
Sources
- ONS: Retail sales, Great Britain: September 2026 (23 October 2026) (reviewed 27 October 2026)
- Herbert Smith Freehills Kramer: CMA launches first investigations into fake and misleading reviews (March 2026) (reviewed 27 October 2026)