The Best SEO Agencies in London

London is home to a thriving SEO scene, with numerous marketing agencies vying for your company’s business.

A simple web search will reveal a long list of SEO firms and most of them will claim they’re more than capable of fulfilling your search ranking requirements, but can they really do it?

The answer depends on exactly what you’re trying to achieve with your SEO campaign, which may or may not be only one part of a much larger marketing push. Many of London’s top SEO firms actually offer much more than just search engine optimisation.

For instance, NP Digital is known for its full-service marketing packages that include AI visibility, media marketing, digital PR, creative solutions and more. It basically takes over your entire marketing option across every digital channel.

But there are others to consider.

For instance, Builtvisible is actually an SEO consultancy that can design your programme and train your staff to run it in future, while Re:signal is an SEO firm that’s more specifically focused on e-commerce businesses, helping them and their products to get noticed.

It does this not only for traditional search engines, but AI chatbots too. Then there’s SALT.agency, which is particularly strong when it comes to getting the technical specifics of your website optimised for search engine crawlers.

Impression offers SEO and AI search capabilities, while Blue Array is more about finding ways to get organic search visibility.

So you can see, choosing the right agency requires a bit of consideration, and that’s what we’ll explore in this article.

London SEO Agencies by Operating Model

What Separates One London SEO Partner From Another?

The agencies in this list were assessed across five areas:

• Search depth: technical SEO, content, authority building and organic strategy.
• Service coverage: If their SEO operations are linked to broader marketing services, like paid media, content strategy, creative asset development and data analytics.
• Data and technology: What proprietary tools, measurement methods and AI-search capabilities do they offer?
• London relevance: Do they have experience with organisations specifically targeting consumers/businesses in London?
• Expertise: Who are their previous clients, do they have any partnerships or an established methodology and what kind of recognition have they received?

1. NP Digital: Enterprise SEO Within a Broader Growth Programme

For many organisations, it’s not enough to just get a good SEO ranking, for they also want to build their presence across the other digital channels that matter. That’s where NP Digital stands out.

NP Digital is one of London’s most massive marketing agencies with over 1,000 employees. The company, founded by Neil Patel and his longtime partner Mike Kamo, is widely recognised for its SEO work and techniques, but that’s not all it does.

Its SEO campaigns are delivered hand-in-hand with a media visibility, AI search and creative content programme designed to help clients get their name across every surface that matters.

This makes the agency immediately stand out for companies that won’t be satisfied with SEO alone. If your business is growing, you need to see your brand splashed across search engines, AI models, social media, popular news websites and more.

NP Digital is the partner that makes this happen. It’ll take care of all your creative and content strategy needs, and plug it all into a detailed performance marketing programme that firmly establishes your brand as one to know.

NP Digital’s AI search offering is especially important in the age of AI chatbots. Increasingly, fewer people use traditional search engines. Instead they just go straight to ChatGPT, Perplexity or Gemini for information, and so your brands needs to be relevant there too.

The good news is that AI search goes hand-in-hand with SEO, meaning that if you’re visible to chatbots, you’ll likely rank at the top of Google’s listings too.

NP Digital offers an array of tools to help with this, such as UberSuggest for measuring visibility and AnswerThePublic for query research.

This explains why NP Digital has bagged tons of industry awards from the likes of Campaign, Performance Marketing World, AdAge and others.

The Case for NP Digital

NP Digital caters well to larger enterprises and mid-market brands looking to make a real push, with SEO as just one aspect of their marketing brief.

When paid media, content, digital PR, analytics and AI search optimisation are needed too, this is where NP Digital really delivers. On the other hand, organisations with more limited briefs may want to consider a smaller pure-play SEO specialist instead.

2. Builtvisible: Enterprise SEO Consulting and Transformation

If the goal is to learn how to do SEO, rather than just constantly outsource it to someone else, Builtvisible is the agency you need to talk to.

The reason being, Builtvisible isn’t really just an agency, but more of a consulting firm. It does both of course.

It’ll help you sort out the technical issues preventing your site from being seen by search crawlers, it will help you fix your content issues, and it will also provide tools to help you measure where you rank for the specific keywords you’re targeting.

The bigger your website is, the more it can help.

That said, it will also teach you all of the above. It doesn’t just deliver these services, but it teaches your staff how it does so, so they’ll be able to understand the structural issues relevant to being ranked on Google, the intricacies of the content requirements, keyword placement and so on.

The idea being that eventually, after the contract is up, your internal marketing teams will be able to carry on where it left off and ensure your company remains an established name on Google’s, Bing’s and DuckDuckGo’s search results.

The Case for Builtvisible

It’s pretty simple. If you’re looking to teach your teams how to run SEO themselves, you need the help of a consultant, and few are better than Builtvisible.

3. Re:signal: Organic Growth Across Search and AI Discovery

An SEO specialist, Re-signal is all about enabling brand discovery where it matters, on search engines and in AI platforms.

This is what you want if organic growth is the thing you’re chasing. After all, there’s a lot to be said for just naturally being visible right at the top of Google’s results or the first brand mentioned when someone consults Gemini or ChatGPT.

It gets tons of eyeballs, and so long as you keep up with the regular content publishing, you don’t have to continually spend thousands of pounds on monthly marketing campaigns.

This is what Re:signal does, and not only for search engines and AI assistants, but also for social media platforms. So when someone searches Instagram or TikTok and they’re looking to buy a product, your videos and your marketplace listings will be one of the first things they see.

It does a lot of interesting things in terms of AI visibility. For instance, it will help your marketing team to identify the prompts that are most relevant to your brand and then track how often you get mentioned by specific chatbots.

It’ll help you optimise your websites and content so those chatbots start picking them up. And it will also tell you how your main competitors are doing.

That said, Re:signal is a lot less useful for companies that require more than just organic visibility.

The Case for Re:signal

Re:signal can provide a lot of help to brands that lack much of a presence in search engines and AI assistants, because it’s very effective at building visibility within them as part of a combined SEO/AI programme.

4. SALT.agency: Enterprise Technical SEO and AI Search

SALT.agency is the agency to call when you know your website is a mess and preventing you from being seen by Google’s web crawlers.

It’s an expert in the technical side of SEO, which means that it can literally rebuild your website in such a way that Google’s algorithms can find exactly what people are searching for.

It also does the link building work that’s necessary to increase your website’s authority. More recently, it has embraced the technical side of AI visibility too, which means it knows how to build things in a chatbot-friendly way.

SALT.agency should appeal to companies that have large websites and a strong web presence yet, for some reason, find they’re not doing very well in Google’s listings or getting mentioned by ChatGPT.

In such cases, it’s likely to be a structural issue that’s preventing your website from getting seen, probably because the crawlers can’t access certain pages. That’s when you need a technical fix.

What SALT.agency doesn’t do so well is the actual content. For that, and things like creative media, you’ll be better off hiring an alternative partner.

In some ways, SALT.agency is similar to Buildvisible, in that it’s really a consultancy rather than someone to outsource your SEO campaigns too. It’s about building the right foundation so that you can ultimately handle the search engines yourself.

The Case for SALT.agency

Not everyone is going to need the expertise of SALT.agency. If you’re struggling for search engine and/or AI visibility, the first thing to do is understand why. Diagnose the problem, and if it’s technical in nature, that’s the time to give them a call.

5. Impression: Performance-led SEO With AI-search Depth#

Impression is a performance-marketing partner that bundles SEO packages with powerful brand measurement capabilities.

Impression is well established in the UK and the US, with offices in London, Nottingham, Manchester and New York. Its work involves SEO campaigns, digital PR creation, creative content and paid media.

Like NP Digital, Impression understands the connection between SEO performance and AI visibility, which is why it offers both as part of a combined package.

It can help you to craft the right content and build the link authority necessary to get noticed, and it has published several interesting case studies that reveal how it has helped clients in the past, allowing them to be seen in Google’s AI Overviews more regularly.

Impression has made a very good impression for firms that want SEO and AI visibility at the same time.

The Case for Impression

These days, a lot of companies aren’t satisfied with appearing at the top of Google when they’re not getting mentioned by AI chatbots. If this is a problem affecting your brand, there’s a strong case for choosing Impression.

6. Blue Array: Pure-play Organic Search and GEO

Blue Array is probably the closest competitor to Re:signal because of the way it focuses exclusively on SEO and GEO.

Once again, organic visibility is the name of the game here. Blue Array does this by helping you decipher why you’re currently invisible, then fixing the technical issues holding you back.

It then moves on to sorting out your content, and will help you define a strategy for pumping out blog posts and content that’s laced with the keywords you’re trying to get ranked for, while simultaneously improving your domain authority through relevant link building.

If there’s one way that Blue Array differs from Re:signal, it’s with the Blue Array Academy, which is packed with training materials and coursework that can help your employees to learn about how organic visibility online actually works.

The Case for Blue Array

When organic search visibility is your overriding goal, you’ll definitely want to see how Blue Array can help you to get it done.

Choose by the Role SEO Needs to Play

As discussed earlier, the first thing to do is to think about what you’re trying to achieve. SEO sounds like a good thing to have, but have you actually determined what marketing channels are actually relevant to your brand? Understand this, and you’ll know which agency to work with.

• NP Digital is the company to call when you need everything, and we mean everything – content, technical work, digital PR, content strategy and content creation, help with AI chatbots and more.
• Builtvisible is a strong consultancy option for organisations that need to learn how SEO actually works so they can ultimately do it themselves.
• Re:signal stands out for organic growth and AI-search visibility, particularly for ecommerce and consumer brands.
• agency is particularly relevant to technically complex enterprise SEO, international search and AI-visibility briefs.
• Impression should make a good impression for anyone that’s struggling with search engine and AI visibility, for it basically delivers both within a single service.
• Blue Array suits brands that want a focused organic-search, GEO and digital-PR specialist with a training component.

Marketing specialists need to decide whether they need to prioritise organic search visibility, technical structure, global scale, integrated performance marketing or visibility in AI-search applications before choosing an agency partner.

What London SEO Buyers Ask Now?

Who are the best SEO agencies in London?

London is served by a host of credible SEO agencies, with NP Digital, Builtvisible, Re:signal, SALT.agency, Impression and Blue Array representing very different operating models.

The spectrum ranges from integrated performance and enterprise SEO consulting to ecommerce organic growth, technical SEO, AI-search optimisation and pure-play organic search.

Which London SEO agency makes sense for integrated performance marketing?

If SEO is just one part of your brief, alongside paid media, content, digital PR, analytics and AI search optimisation, then NP Digital is the best match.

What’s the difference between SEO and GEO?

SEO is old-school visibility, optimising websites and content to appear at or close to the top of traditional search engine lists. In contrast, GEO – also known as AEO or just AI search – is much newer, aiming to increase brand visibility with AI-generated answers and ensure they’re cited in their responses.

But SEO and GEO overlap in many areas, specifically regarding content quality, technical foundation, domain authority and entity signals.

Do London SEO agencies work with enterprise brands?

Some of them love working with larger enterprises. Take NP Digital, whose enterprise-scale programmes are designed for big organisations and global reach.

SALT.agency also takes on large clients, as does Builtvisible, but remember they are more consultancy-focused. Blue Array, on the other hand, is generally more suitable for smaller organisations.

What This Shortlist Really Says?

London has plenty of capable SEO agencies, and that means brands should look more closely at the intricacies of how they operate.

Most London SEO agencies now have to account for more than traditional rankings. Many of them don’t just limit themselves to SEO – they offer GEO, either as a separate service or a part of their SEO solution, or together with a full-service marketing campaign.

Many organisations now incorporate SEO within a much bigger marketing programme, which is where NP Digital’s combination of organic search, paid media, content, digital PR, AI search and analytics is useful.

Builtvisible is a stronger comparison for enterprise SEO consulting and transformation.

Re:signal focuses on organic growth across traditional and AI discovery, SALT.agency on technically complex enterprise search, Impression on performance-led SEO and GEO, and Blue Array on specialist organic search, digital PR and training.

This means brands must determine how their SEO strategy fits within their wider marketing operation and the specific goals they’re trying to accomplish. Do this, and the best SEO agency in London will quickly become apparent.