Search "best AI consultancy UK" and you will find the same pattern in every result: a five-person boutique sitting in the same numbered list as a firm with 150 staff and FTSE-100 clients, with no distinction made between them. That is not a ranking. It is a name list. We checked what actually differs by size, using Companies House filings and independently reported facts rather than firm marketing, because size changes what you should expect more than almost anything else on the list.
What "AI consultancy" actually spans
Deloitte and a two-person London studio both call themselves AI consultancies. So does everything in between: global integrators running multi-year transformation programmes, mid-size specialist firms with dozens of staff, and boutique studios with a handful of named people. Treating all three as comparable options on one list obscures the one thing that predicts what an engagement will actually feel like, which is who is in the room.
How we checked
Most "best AI consultancy" content is written by one of the consultancies on its own list, and most of what these sites publish about themselves, team size, client outcomes, years in business, is unverified. We cross-checked the firms that came up most often against Companies House incorporation records, LinkedIn headcount bands, and independently reported news, and we have flagged clearly below where a figure is the firm's own claim rather than something we could independently confirm.
The enterprise tier
Deloitte, PwC, KPMG, EY, Accenture, which acquired Faculty in March 2026, McKinsey QuantumBlack, IBM Consulting, Capgemini, and Cognizant sit in this tier. Public pricing data, via G-Cloud and industry sourcing guides, runs from roughly £150,000 to £3m or more per engagement, with teams sized in the dozens to hundreds. This tier is built for multi-country transformation programmes, not a single scoped pilot.
The mid-size specialist tier
These firms are UK-based, AI-focused or AI-adjacent, and meaningfully larger than a boutique, though most do not publish pricing for small, fixed-fee work. Aiimi has approximately 155 to 180 employees according to filed accounts and PitchBook, and was founded in 2007. Its named public-sector clients include a reported £24m, eight-year data and AI framework with Anglian Water, covered by Computer Weekly, and the Financial Conduct Authority.
Elsewhen shows approximately 32 UK employees on record, though the firm describes 100 to 150 staff group-wide. It was founded in 2011, and its case studies name Spotify and Mastercard as clients. SoftBlues has headcount estimates ranging from roughly 30 to 200 depending on the source, its current UK entity was registered in 2022, and it publishes fixed pricing starting at £10,000 to £20,000 for a discovery phase, the closest thing to transparent pricing anywhere in this tier.
Neurons Lab markets "50+ AI engineers," but the UK-registered entity shows five employees on record, suggesting most of the team sits outside the UK. It is a financial-services specialist, with named references including HSBC and Visa on the training and enablement side. Pulsion has approximately 36 employees and was incorporated in 1995, over 30 years trading, as a general software consultancy with AI as one service line rather than an AI-only practice.
RSK Business Solutions has approximately 28 UK employees and is part of the much larger RSK Group. Its dedicated AI service line only launched in August 2025, so the AI practice itself is about a year old despite the parent company's longer history. Deeper Insights was, for about a decade, an independent 11 to 22 person AI boutique. It was acquired by Cisco in October 2024 and no longer operates as an independent firm, so it should not appear on comparison lists as one.
The boutique fixed-fee tier
This is the tier almost no comparison list distinguishes, and it is where Kelriva actually sits. theaiconsultancy.ai is the closest genuine size match we found: five named core team members, with its UK entity incorporated in December 2024, publishing fixed-fee packages starting at £3,500 for a readiness sprint and £15,000 for a discovery and pilot phase.
Kelriva AI is two founders with no wider bench. Fixed-fee packages run from a free 2-minute AI Readiness Score, through a £4,500 full AI Readiness Assessment and an £8,500 IDP Proof of Concept, up to a £15,000 LangGraph Agent MVP.
What size actually changes for you as a buyer
At a 150-person firm, the person who scoped your call is often not the person who ends up doing the work, and you may not know the actual team composition until the statement of work is signed. At a boutique, there usually is not anyone else to hand it to. Neither model is better by default. A multi-country data platform rollout needs bench depth a two-person studio does not have. A scoped, fixed-fee readiness assessment or proof of concept does not need it, and paying enterprise-tier rates for it is paying for capacity you will not use.
Questions worth asking before you sign with anyone on any list
Ask how many people will actually touch your project, by name. Ask whether the team size you were quoted is for the UK entity or a global group figure. Ask whether pricing is fixed, or day-rate with scope that can expand. And ask how old the specific legal entity you are contracting with is, not the parent brand, since several firms on these lists have been acquired, rebranded, or re-incorporated in the last two years.
Is a bigger AI consultancy always the safer choice?
Not automatically. Larger firms bring bench depth and delivery capacity that suit large, multi-year programmes, but that scale is priced in whether or not your project needs it. For a single scoped deliverable, a smaller firm with a fixed fee and direct founder involvement is often the better-matched choice, not a compromise.
How is Kelriva AI sized compared to other UK AI consultancies?
Kelriva AI is a two-founder studio, comparable in scale to theaiconsultancy.ai and smaller than every mid-size or enterprise firm in this comparison. That is a deliberate shape for the scoped, fixed-fee work we take on, not a limitation we are working past on that work. It is a real limitation for anything else: no wider bench if either founder is unavailable, and no specialist coverage outside the three service lines we actually deliver, the same trade-off we flag above when a mid-size firm's AI practice turns out to be a year old despite an older parent brand.
Why do so many "best AI consultancy" lists look the same?
Most are written by one of the consultancies included in the list, as a marketing exercise, and few disclose that. None of the ten UK lists we reviewed distinguished firms by size or checked their own headcount claims against Companies House or LinkedIn data.
Sources
Accenture completed its acquisition of Faculty on 16 March 2026, per Accenture's newsroom. Deeper Insights was acquired by Cisco on 3 October 2024, per Cisco's official acquisitions list.
Aiimi's reported £24m, eight-year Anglian Water framework is covered by Computer Weekly. Elsewhen's Spotify and Mastercard relationships are published as named client testimonials on Elsewhen's own site.
Neurons Lab's UK entity has filed full company accounts (not micro-entity or dormant accounts) in each of the last three years, per its Companies House filing history, most recently for the year to 31 October 2025. Pulsion Technology's 1995 incorporation is on the public register, company number SC156453.
RSK Business Solutions' new AI service line was reported in late August 2025 by MediaBrief. theaiconsultancy.ai's fixed-fee pricing is published on its own pricing page.
Employee ranges for Aiimi, Elsewhen, SoftBlues, and RSK Business Solutions combine filed Companies House accounts with LinkedIn headcount bands and, where stated, the firm's own published figures. These change over time; last checked September 2026.