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Depth over breadth
The best agencies have genuine specialists in each discipline — not account managers who "do a bit of everything". Ask who specifically will work on your SEO, PPC, and content.
2026
Updated
London has 4,000+ digital marketing agencies. Most are generalists who do everything adequately and nothing exceptionally. Here's how to find the exceptions.
The best agencies have genuine specialists in each discipline — not account managers who "do a bit of everything". Ask who specifically will work on your SEO, PPC, and content.
Traffic graphs aren't results. The best agencies show: revenue attributed to marketing, cost per lead trends, client retention rates, and before/after comparisons.
Agencies that hide pricing are either expensive or inconsistent. The best publish their rates and let you compare. Secret pricing protects the agency, not you.
In 2026, any agency that doesn't mention AI Overviews, ChatGPT citations, or GEO is already 18 months behind. This isn't a nice-to-have — it's core SEO strategy.
12-month minimums protect the agency. 90-day minimums are fair — enough time to prove results, short enough to leave if they don't deliver.
Run the agency's own website through PageSpeed Insights. Check if they rank for their own keywords. If their marketing doesn't work for themselves, it won't work for you.
The London digital marketing agency market is the most competitive in the UK, with over 4,000 agencies competing for attention. Average retainer costs range from £2,500-£15,000/month for full-service marketing. The market is heavily consolidated at the top (large networks) and fragmented at the bottom (2-5 person shops). The sweet spot is mid-market boutique agencies with 15-50 staff who combine depth of expertise with senior-level attention.
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