18 Best SEO Agencies London [2026]: Pricing, Specialisms & Honest Comparison

The best SEO agencies in London range from enterprise firms like Brainlabs and Impression Digital (£5,000–£25,000+/month) to specialist boutiques like ClickSlice and Whitehat SEO (from £1,967/month). We profiled 18 agencies across 3 tiers with actual GBP pricing, AEO capabilities, and verified case study results. This article includes our own agency — with full disclosure.

Full Disclosure

Whitehat SEO is included in this comparison at position #15 (alphabetical within the Specialist tier — not #1). We are a London-based HubSpot Diamond Solutions Partner. We've profiled every agency using the same criteria and methodology. Where our services are relevant, we've linked to them — and we've been equally honest about our limitations as about our strengths.

London HQ (global) · Founded 2012 · 900+ staff · Google Marketing Platform Partner

The largest agency on this list by headcount. Brainlabs acquired Distilled (one of the original London SEO consultancies, founded 2005) in January 2020, inheriting deep organic search expertise and the SearchLove conference. They serve global brands including TUI, Formula 1, Vodafone, American Express, and Deliveroo.

Best for: Enterprise brands needing integrated paid + organic + CRO under one roof at global scale.

Case study: Reduced cost-per-trial from £50 to £20–30 for Which?; 43% CPA reduction for a major travel brand.

London + Nottingham HQ + Manchester · Founded 2012 · 120+ staff · B Corp Certified

One of the most awarded UK agencies — Digital Agency of the Year and Independent Agency of the Year at the 2023 European Agency Awards. B Corp certification signals genuine commitment to ethical business practices. They serve enterprise clients including Clarins, Specsavers, Topps Tiles, and Cancer Research UK, with growing B2B credentials through clients like Tensar.

Best for: Mid-to-large businesses wanting an ethically certified agency with strong digital PR and technical SEO.

Case study: Topps Tiles — 108% organic traffic increase, 76% organic revenue increase within 12 months.

London + Sheffield HQ + Manchester + New York · Founded 2019 · 60–100+ staff · 79 awards

The fastest-growing agency on this list, Rise at Seven pioneered the concept of "social SEO" — optimising for TikTok and Instagram search alongside traditional Google. Founded by Carrie Rose (Forbes 30 Under 30), they've amassed 79 awards in just six years. Clients include Xbox, PlayStation, Klarna, and PrettyLittleThing.

Best for: Consumer and D2C brands wanting creative, PR-driven SEO with strong social media integration.

Limitation: Less suited to traditional B2B — their strength is viral, consumer-facing creative campaigns.

32 London Bridge Street, London · Founded 1999 · 2,000+ staff globally · RAR Digital Awards ×3

The true enterprise option. Jellyfish serves 49 of the world's top 100 advertisers through 38 offices globally, offering international SEO in 150+ languages. Now part of The Brandtech Group (acquired 2023), they're a Google Marketing Platform Certified Partner, Analytics 360 partner, and Google Cloud partner. Clients include Samsung, Adidas, eBay, Uber, and Harrods.

Best for: Global brands requiring multi-language, multi-market SEO with deep Google platform integration.

The Bard Building, 20 Curtain Road, London EC2A · Founded 2011 · 500+ in-house + 2,400 freelance · IPA Member

Croud's unique model combines 500+ in-house staff with 2,400+ vetted freelance specialists ("Croudies"), giving them reach across 107 countries and 70+ languages. Their proprietary Croud Control technology manages campaigns at scale. Clients include Audible, Amazon Prime Video, Vans, and Honda. Organic Team of the Year at the Drum Search Awards.

Best for: Multi-market enterprises needing SEO across dozens of countries and languages simultaneously.

Reading HQ + London office · Founded 2015 · 50–70 staff · B Corp · SEO Agency of the Year 2022 & 2023

The UK's largest specialist organic search agency — they do SEO and nothing else, operating a unique "consulgency" model (consultancy + agency hybrid). B Corp certified. The only approved GOV.UK Digital Marketplace supplier of SEO services. Among the first UK agencies to offer GEO (Generative Engine Optimisation). Clients include RAC, Yell.com, Mail Online, and GoCardless.

Best for: Organisations wanting pure SEO expertise without the distraction of other services.

Case study: GoCardless — won a Global Search Award. Monsoon Accessorize — Best SEO Campaign (European Agency Awards 2021).

London · Founded 2009 · Now part of Brave Bison (200+ group) · Google Business: 5.0/5

Founded by Richard Baxter, Builtvisible built a reputation for technical SEO excellence before being acquired by publicly listed Brave Bison in 2025. The acquisition added social media, influencer marketing, and paid media capabilities. Clients include Icelandair, Asda, Aviva, and Superdrug.

Best for: Brands wanting technical SEO backed by a publicly listed media group with broader digital capabilities.

35 New Broad Street, London EC2M · Founded 2008 · 30–40 staff · Clutch: 5.0/5 (10 reviews)

A strong choice for regulated industries — financial services, iGaming, and healthcare. Originally launched as SEO Positive in 2008 before rebranding in 2012, they have deep experience navigating compliance constraints. Winners at the European Search Awards, Drum Search Awards, and UK Digital Growth Awards.

Best for: Regulated-sector businesses (finance, gambling, healthcare) needing SEO within compliance frameworks.

Case study: 35,000 organic monthly hits within a year (target was 20,000 in six months); 25% revenue increase.

Remote-first + London presence · Founded 2012 · 80+ staff · Best Large SEO Agency 2024 · 4-day work week

Reboot has the largest data science team of any search-led agency, giving them a genuinely data-driven approach to SEO. They operate a four-day work week — which tends to attract higher-calibre talent. Best Large SEO Agency of the Year at the 2024 UK Search Awards. Clients include OnBuy.com, Confused.com, Forbes, and Viator. They also offer digital PR in 10+ languages and are among the early adopters of GEO services.

Best for: Businesses wanting analytically rigorous, data-driven SEO with strong multilingual digital PR.

London · Founded 2017 · 10–25 staff · SEMrush Academy Trainers · Published NPS: 80 · 4-day week

Type A Media punch above their weight. They authored the SEMrush site audit course and serve enterprise clients including eBay, Just Eat, Brewdog, and Foxtons despite being a relatively small team. Strong B2B credentials via Gerald Eve (property), Investment News, and University of Cambridge. They use proprietary REST and BOOM frameworks, and their published NPS score of 80 signals exceptional client satisfaction.

Best for: Mid-market businesses wanting senior-level expertise and frameworks from industry educators.

London · Founded ~2015 · 10–25 staff · Best SEO Campaign 2025 (European Search Awards) · Clutch: 5.0/5

The strongest pure B2B credentials of any agency on this list. Polaris serves Sodexo (FTSE 250 — across four business units), Dune London, Reachdesk (B2B SaaS), and Abacum (financial SaaS). Their Best SEO Campaign 2025 win at the European Search Awards was described by judges as "genuinely clever." They offer AI search optimisation alongside traditional SEO, content, and digital PR.

Best for: B2B companies wanting a specialist agency that understands long sales cycles and complex buying committees.

Case study: Dune London — 600%+ increase in SEO performance within 7 months. 200%+ increase in qualified leads within 3 months.

London + Sheffield HQ + Leeds · Founded 2008 · 80+ staff · Google Premier Partner · Google Business: 4.9/5

Certified Google Premier Partner (the top 3% of Google partners — rare for an SEO-focused agency) and also Bing Accredited. They serve enterprise clients including Decathlon, NHS, and Zoho alongside mid-market businesses. SEO Agency of the Year at the UK Digital Growth Awards. They offer GEO services alongside traditional SEO, PPC, and digital PR.

Best for: Businesses wanting an established, Google-accredited agency with the reassurance of public sector (NHS) credentials.

4th Floor, Holborn Tower, London WC1V · Founded 2012 · ~47 staff · Google Premier Partner 2025 · Clutch: 28 reviews

Recently acquired by Pixis.ai (an AI-powered marketing platform), giving them access to proprietary AI tools. Google Premier Partner 2025 with strong B2B credentials through clients like Knight Frank, Octopus Investments, and Nutanix. They offer flexible retainers from £2,000/month covering SEO, PPC, paid social, GEO, and international SEO.

Best for: B2B companies wanting AI-enhanced SEO with the flexibility of a mid-sized agency.

Case study: 249% organic click increase; 250% organic transaction increase.

Soho, Central London + Los Angeles · Founded ~2012 · 15–30 staff · UK/European Search Awards winner

Go Up has built deep expertise in specific verticals: legal, recruitment, and property SEO. They combine SEO with digital PR as a unified service rather than treating them separately. They also offer AI search optimisation across ChatGPT, Gemini, and Perplexity. Company Culture Awards for Mental Health and Transformative Culture suggest good staff retention.

Best for: Legal firms, recruitment agencies, and property companies wanting sector-specialist SEO.

Case study: 225% organic traffic increase within 18 months; 96% boost in appointment leads in 6 months.

This is us — full disclosure. We publish this article and have profiled ourselves using the same criteria as every other agency.

80A Uxbridge Road, London W12 8LR · Founded 2011 · 5–15 staff · HubSpot Diamond Solutions Partner

Our core differentiator is the intersection of B2B inbound marketing and HubSpot SEO — we build organic search strategies that integrate directly with HubSpot CRM for closed-loop attribution. We run the world's largest HubSpot User Group (London HUG), and our CEO is a guest lecturer at UCL. We offer a dedicated Answer Engine Optimisation service alongside traditional SEO, PPC, and content strategy.

Published pricing: SEO from £1,967+VAT/month, inbound marketing from £5,000+VAT, HubSpot onboarding from £980+VAT, PPC from £780+VAT.

Best for: B2B companies on HubSpot wanting SEO that integrates with their CRM for measurable pipeline attribution.

Honest limitations: We're a small team — we don't have the capacity for multi-market international campaigns or large ecommerce operations. If you need 50-language rollouts, look at Croud or Jellyfish. If you need creative viral campaigns, Rise at Seven is better suited.

Explore further: Our SEO services · Free website audit · SEO pricing guide

Shoreditch Stables, 138 Kingsland Rd, London E2 · Founded 2016 · 10–15 staff · Google Business: 4.9/5 (94 reviews)

ClickSlice currently ranks #1 organically for "SEO agency London" — the strongest self-ranking signal of any agency on this list. Founded by Joshua George (best-selling Udemy SEO course with 169,000+ students, Forbes and Entrepreneur featured), they specialise in ecommerce SEO using a data-driven reverse-engineering approach. No lock-in contracts and a 90-day money-back guarantee signal confidence. Hired by the UK Government for SEO training.

Best for: eCommerce businesses wanting a proven, data-driven approach with no contract lock-in.

Case study: £100M+ ecommerce sales generated across clients; 15% organic sales increase within 3 months.

Kemp House, 152–160 City Road, London EC1V · Founded 2016 · 10–20 staff · Clutch: 5.0/5 (27 reviews) · Best SEO Company 2023 (Clutch)

The strongest review profile relative to their size — 5.0/5 on Clutch from 27 verified reviews plus 88 Google reviews. Named Best SEO Company by Clutch in 2023. They serve SMEs across SEO, PPC, local SEO, ecommerce, and web development. Clients consistently report minimum 300% ROI.

Best for: SMEs wanting a well-reviewed, full-service digital partner with strong local SEO capabilities.

Case study: +800% leads for a B2B SaaS brand; +1,452% online sales increase; +378% organic traffic.

London (remote) · Founded 2016 · 2–9 staff · Clutch: 4.8/5 (3 reviews)

The most niche agency on this list — a micro-boutique focused exclusively on SaaS SEO and B-Corp business growth. Their revenue-driven approach focuses on go-to-market acceleration and in-house team training alongside execution. Project-based pricing (around £8,000 per project) rather than ongoing retainers suits businesses wanting specific deliverables.

Best for: SaaS companies wanting a specialist micro-agency focused on revenue-driven organic growth.

How much does SEO cost in London in 2026?

London SEO costs range from £500 to £20,000+ per month depending on scope and agency tier. Small businesses typically pay £500–£2,000/month, mid-sized companies £2,500–£5,000, and enterprises £5,000–£20,000+. London agencies charge a 20–40% premium over regional equivalents. The UK median sits around £975/month.

How long does SEO take to show results?

SEO typically takes 3–6 months for early improvements and 6–12 months for significant results in competitive markets. Technical fixes can show impact within weeks, while content and link building compound over time. Most UK B2B companies break even on SEO investment at approximately 9 months.

What does an SEO agency actually do?

A professional SEO agency diagnoses technical and content issues limiting your visibility, then systematically improves them. Core services include technical audits, keyword research, on-page optimisation, content strategy, link building or digital PR, and local SEO. Good agencies provide monthly reporting and strategy adjustments based on performance data.

Is it worth paying for SEO for a small business?

Yes. SEO delivers one of the highest ROIs of any marketing channel — a median 748% over three years. Unlike paid ads that stop when budget runs out, SEO builds cumulative visibility delivering leads long-term. Even modest budgets of £500–£1,500 per month can drive meaningful local results for small businesses.

How do I know if my SEO agency is doing a good job?

Check three things monthly: organic traffic trends in Google Analytics, keyword ranking movements, and — most importantly — leads or sales from organic search. Your agency should provide transparent reporting connecting their work to business outcomes. Verify claims independently via Google Search Console.

Can an SEO agency guarantee first page rankings?

No reputable agency can guarantee specific Google rankings. Google itself warns against agencies making such promises. Rankings depend on algorithm changes, competitor activity, and market conditions beyond anyone's control. A good agency guarantees transparent processes, ethical tactics, and measurable progress toward agreed KPIs.

Should I choose a specialist SEO agency or a full-service digital agency?

Choose a specialist if search is your primary growth channel or you operate in a competitive niche requiring deep expertise. Choose full-service for integrated marketing under one roof. Many mid-market businesses use a hybrid approach: specialist SEO agency plus in-house marketing coordination.

What are the red flags when choosing an SEO agency?

Key red flags include guaranteed rankings, no site audit before quoting, reluctance to explain methods, buying backlinks or using PBNs, focus only on rankings rather than business outcomes, pressure to sign long-term contracts immediately, no access to your analytics, and promising results within 30 days.

Do I need SEO if I already run Google Ads?

Yes. SEO and PPC complement each other. PPC delivers immediate visibility while SEO builds long-term traffic that reduces paid dependency. SEO delivers a median 748% ROI versus approximately 200% for PPC. Together they stabilise your lead pipeline — PPC fills short-term gaps while SEO compounds returns over time. See our pricing comparison for more.

What should be included in an SEO agency contract?

Essential elements include clearly defined scope with measurable deliverables, reporting cadence and data access, data and IP ownership clauses, cancellation terms with 30–60 day notice periods, payment schedule tied to deliverables, backlink policy, and performance review milestones at 90-day intervals.

Not Sure Where to Start?

Before you approach any agency, understand your current SEO position. Our free audit analyses your technical health, keyword rankings, content gaps, and competitive landscape — giving you the baseline you need to evaluate proposals with confidence.

Methodology: Agencies were selected based on demonstrable London presence, verifiable case studies, minimum three years trading history, presence on verified review platforms, and evidence of adapting to AI search changes. Pricing ranges are estimated from Clutch data, published rates, and industry benchmarks. B2B strength ratings reflect depth of B2B client portfolio and case studies. AEO/GEO capability reflects whether the agency offers a named AI search service. Whitehat SEO Ltd is the publisher of this article and is included with full disclosure. This article was last updated February 2026 and will be reviewed quarterly.