# Best AI Agencies for Retainer Work in London

> 8 agencies. Top-ranked: Found, ClickSlice, NOVOS.

Canonical page: https://www.aiagencies.eu/for/retainer/london
Generated: 2026-09-28 · Curated by Gabor Kiss · No paid placements — inclusion, score, and rank are never sold.

## Ranked roster
1. **Found** — London, United Kingdom · €85-130/hr (directory-listed) · team 50-249 · founded 2005 · services: AI SEO, AI Marketing, AI Automation · 8 documented client engagements with source URLs · reviewed 2026-09-23 · https://www.aiagencies.eu/agency/found
2. **ClickSlice** — London, United Kingdom · rate not published · team 10-49 · founded 2016 · services: AI SEO · 6 documented client engagements with source URLs · reviewed 2026-09-24 · https://www.aiagencies.eu/agency/clickslice
3. **NOVOS** — London, United Kingdom · €130-170/hr (directory-listed) · team 10-49 · founded 2018 · services: AI SEO, AI Marketing · 5 documented client engagements with source URLs · reviewed 2026-09-23 · https://www.aiagencies.eu/agency/novos
4. **Imobisoft** — London, United Kingdom · €45-85/hr (directory-listed) · team 10-49 · founded 2009 · services: AI Consulting, AI Development, Generative AI · 4 documented client engagements with source URLs · reviewed 2026-09-04 · https://www.aiagencies.eu/agency/imobisoft
5. **Ekimetrics** — London, United Kingdom · rate not published · team 50-249 · founded 2006 · services: AI Consulting, AI Marketing, Generative AI · 8 documented client engagements with source URLs · reviewed 2026-09-07 · https://www.aiagencies.eu/agency/ekimetrics
6. **Faculty** — London, United Kingdom · rate not published · founded 2014 · services: AI Consulting, AI Development, AI Automation, AI Agents · 3 documented client engagements with source URLs · reviewed 2026-08-04 · https://www.aiagencies.eu/agency/faculty-ai
7. **Neurons Lab** — London, United Kingdom · rate not published · team 50-249 · founded 2019 · services: AI Consulting, AI Agents, AI Development, Generative AI · 2 documented client engagements with source URLs · reviewed 2026-08-04 · https://www.aiagencies.eu/agency/neurons-lab
8. **The AI Consultancy** — London, United Kingdom · rate not published · services: AI Consulting, AI Development, Generative AI, AI Agents · 2 documented client engagements with source URLs · reviewed 2026-08-04 · https://www.aiagencies.eu/agency/the-ai-consultancy


## About this market
London's retainer bench splits into two kinds of ongoing work, and the documented evidence tells them apart. On the systems side, Faculty's long-standing NHS partnership built technology supporting NHS Gold Command, and the firm runs an AI Operations service line to maintain what it deploys; Imobisoft pairs short builds with ongoing support, including a two-year Treasury Today engagement, behind operational platforms such as MirZyme's preeclampsia-risk tool; Neurons Lab describes forward-deployed engineers and iteration after deployment; The AI Consultancy sells a Fractional AI Officer on a monthly fee next to MoverAI, a video-survey platform generating revenue since June 2025. On the marketing side the retainer buys movement: NOVOS reports Osprey's share of AI answers up 21.4 points in twelve months, ClickSlice says over 90% of its clients stay long term and publishes before-and-after AI visibility for Furl and National Private Investigators, Found runs monthly SEO retainers alongside its Secret Sales demand model, and Ekimetrics brings marketing-mix modeling, with Eurostar its named case.

The sorting question is what the monthly fee is buying: a system kept running, or a number kept moving. For a deployed system, ask for the monitoring, retraining and exit terms, and whether you could take the system in-house. For a search or marketing retainer, the curator notes that the AI-visibility figures here rarely name their prompt set or tracking tool, and that NOVOS prices against its own score—agree a metric you can measure independently before the first invoice.

## Questions buyers ask

### How many AI agencies work with retainer in London?
8 agencies in our directory combine verified retainer client evidence with a London base. The current top-ranked are Found, ClickSlice, NOVOS — ordered by depth of documented client evidence, then our editorial scoring (portfolio quality, credibility, completeness); placement is never paid.

### How much does an AI agency cost in London?
Published rates across this page's agencies run €45–170 per hour (median ~€108). Project totals depend on scope — the rate index at /rates breaks the computed bands down by region, country and team size.

### How is the retainer model verified?
Every agency here documents retainer work on its own site or in a published case study, describing the engagement structure rather than a service-list claim. We never infer the model from portfolio tone, so this list only contains agencies that operate retainer engagements deliberately.

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Source: AIAgencies.eu — the curated register of European AI agencies. Rate provenance: "agency-confirmed" = disclosed via submission or claimed profile; "directory-listed" = Clutch or two agreeing B2B directories (lone unverified sources are never written). Full method: https://www.aiagencies.eu/methodology · Rate index: https://www.aiagencies.eu/rates