Compare London SEO agencies on four things: size, specialism, how they charge and the proof they can show. Ask every one the same questions.
The best SEO agency in London for your business is the one that can prove results in your sector, explain how it will bring in leads rather than traffic, and put a named team on your account. Compare every shortlisted agency on four things: size, specialism, how it charges and the proof it can show.
London has more SEO agencies than any other UK city, from one person consultancies to networks with hundreds of staff. That choice is useful, but it also means pitches blur together. Most agencies will tell you they are data driven, transparent and focused on ROI.
The way through is to stop listening to claims and start comparing evidence. This guide gives you a simple framework you can use in your first calls, plus the questions that separate agencies that can deliver from agencies that are good at pitching.
Agency size: big network, mid-size or specialist
The right size depends on how much attention your account will get, not on how impressive the client logos look. A small account at a large agency often ends up with a junior team, while a large account can swamp a two person shop.
| Agency type | Usually good for | Watch out for |
|---|---|---|
| Large network agency | Enterprise brands with big budgets and many markets | Senior people in the pitch, juniors on the work |
| Mid-size independent | Growing businesses that want a full team and direct access to leaders | Stretching into services they don’t really offer |
| Specialist agency | Businesses in one sector, such as B2B, SaaS or fintech | Limited capacity, so ask about start dates |
| Freelancer or consultant | Small sites, audits and one off projects | Holidays, illness and no cover |
Ask every agency who will do the work each week and how many other clients that person looks after. A clear, specific answer is a good sign.
Specialism: why sector experience matters
An agency that already knows your sector will get to results faster because it understands your buyers, your competitors and the searches that lead to sales. A generalist has to learn all of that on your budget.
This matters most when the sale is complex. If you sell to other businesses, a specialist B2B SEO agency will already know how to target buying committees, long sales cycles and low volume, high value keywords. Our guide to choosing a B2B specialist or a generalist goes into this in more detail.
Ask for two examples from businesses like yours, with the starting point, what changed and how long it took.
Pricing models and what they tell you
How an agency charges tells you how it thinks about the work. There are three common models in London:
- Monthly retainer. A fixed fee for an agreed scope each month. Best for ongoing SEO, as long as the scope is written down.
- Project fee. A fixed price for a defined piece of work, such as an audit or a site migration.
- Day rate. Time billed as it’s used. Flexible, but harder to budget.
Whatever the model, ask what is included, what counts as extra, and how much notice you need to give. Long minimum terms with no break clause are worth questioning. If you’re weighing up the cost of hiring instead, our breakdown of in-house SEO or an agency compares the real costs side by side.
Proof: what to ask every agency to show you
Proof means results you can check, not awards or follower counts. Ask each agency for:
- Case studies with named clients, or at least named sectors, and real numbers.
- A sample monthly report, so you can see whether it tracks leads or just rankings. Our guide to what a good SEO agency report should show lists what to look for.
- A view on AI search. Buyers now use ChatGPT, Gemini and Google’s AI Overviews to shortlist suppliers, so ask how the agency gets clients cited there. This is the core of AI SEO.
- A rough plan for the first 90 days, based on a quick look at your site.
- A client you can speak to.
If an agency promises first page rankings or guaranteed results, treat that as one of the red flags when hiring an SEO agency. Nobody controls Google’s results.
A simple scorecard for comparing London agencies
Score each agency from 1 to 5 on the points below after your first call, then ask the top two to put their proposal in writing.
| Criteria | What a 5 looks like |
|---|---|
| Sector proof | Two or more relevant case studies with numbers |
| Team | Named people, with a clear weekly time commitment |
| Focus on leads | Reports tie SEO to enquiries, not just traffic |
| AI search | A clear plan for visibility in AI answers |
| Contract | Clear scope, fair notice period, no hidden extras |
Do they need to be based in London? Not necessarily. Meeting in person helps some businesses, but specialism and proof matter far more than postcode.
Where Circulate fits
We work with London businesses on SEO and AI search, with a focus on leads rather than traffic. You can see how we work in the capital on our London SEO page.
If you’re comparing agencies in London, book a free strategy session and put us through the same scorecard.
Related reading: our guides to whether you need a GEO agency and an SEO agency and how long B2B SEO takes to bring in leads.
Common questions
How do I find the best SEO agency in London?
Shortlist three or four agencies, then compare them on sector proof, the team who will do the work, how they report on leads, their plan for AI search and their contract terms. Score each one and ask the top two for a written proposal.
Does my SEO agency need to be based in London?
No. Meeting in person can help, but sector experience, proof of results and a clear plan matter far more than where the office is.
What pricing models do London SEO agencies use?
Most use a monthly retainer for ongoing work, a project fee for defined jobs such as audits, or a day rate. Whatever the model, check what is included and what notice period applies.
What questions should I ask an SEO agency before hiring?
Ask who will do the work each week, for case studies with real numbers, for a sample report, how they handle AI search and what they would do in the first 90 days.
