Clay agencies in the United Kingdom help B2B teams turn Clay tables into booked meetings. Clay makes enrichment cheap. Turning that data into pipeline still takes real engineering skill.
I worked through the UK partners in Clay's own directory alongside the certified Forge Experts. Then I read their case studies, pricing pages and terms.
I judged each Clay agency on build ownership, data quality, sending discipline and honest reporting. Three certified Forge Experts take the top slots. Seven UK boutiques follow.
For another market in the same format, see my list of lead generation agencies in Sydney.
B2B Boosted builds bespoke outbound systems with Clay at the centre. Founder Tim Yakubson says the goal is for clients to fire the agency within three to six months.
Everything gets set up inside accounts you own. There is no minimum commitment and no termination clause. That flexibility is rare on this list.
What stood out to me was the evergreen campaign model. Lead lists refresh automatically inside Clay. Nobody has to top them up by hand.
One client credits a B2B Boosted LinkedIn system with £50k+ in revenue in 43 days. Tim also teaches Clay through a paid course. My guide to Clay lead generation covers the same building blocks.
Vanderbuild splits its work into two halves. One half runs outbound campaigns. The other cleans and enriches the CRM underneath them.
The team finished second globally at the Clay Cup and first in Europe. In 2025 it launched over 250 outbound campaigns. It also built 50+ revenue engines across Europe, the UK and the US.
I liked the pricing flexibility. You can pick a monthly retainer, a project build or payment per warm lead. One client reported 4 SQLs and a 55% LinkedIn reply rate from a demand test.
Every system runs inside your own accounts. The CRM scoring and routing work is what I would expect from a senior GTM engineer.
Growth Alliance is a small fractional team of former CMOs, COOs and CTOs. It builds revenue operations infrastructure for B2B companies between $5M and $50M ARR.
Clay sits beside Cargo, Swarm and HubSpot in their stack. The work covers ABX orchestration, CRM enrichment and revenue attribution.
The capacity model is refreshingly clear. They take four to six clients at once, with 100 to 120 hours each per month. Systems are built in code and documented as they ship.
Coverage runs sixteen hours a day across US and EU time zones. If you are unsure which discipline you need, read GTM engineering vs RevOps first.
Engineered GTM is a founder-led London team run by Jake Gill. It placed first among UK teams at the 2025 Clay Cup.
The pitch is an engine built on your own closed-won data. You do not pay for a build phase until its spec is met and verified.
The free GTM Scorecard is a sensible first step, since it prices your missing pipeline in minutes. Scoring and routing sit on top of Clay enrichment waterfalls tuned to your data.
GTM Studios calls itself the UK's first GTM engineering agency. It also holds a badge as one of Clay's first 100 Solutions Partners.
Outreach triggers on more than 20 buying signals, from funding rounds to champion job moves. Their stated average time to first pipeline is 30 days.
One client reports its ABM account-to-meeting rate rising from 0.5% to 2%. Named clients include Hyperoptic and law firm Harper James. Expect a three-month minimum engagement.
Fuelius is a HubSpot Elite partner with offices from Chester to London. It says it is the only UK HubSpot partner with Clay Enterprise Partner status.
Its in-house GTM team pairs outbound architects with data specialists and CRM strategists. Clay handles enrichment and triggers across email, LinkedIn, WhatsApp and SMS.
The client list is heavier than I expected, with Munich Re, Emirates and Darktrace. Fuelius also builds websites. Confirm who on the team owns your Clay work.
Spring Drive was the fourth official Clay Expert in the UK. It calls itself a positioning-led GTM engineering lab.
Messaging comes first here, then the automation. The team separates resonant signal data from surface signals that every competitor can buy.
For Blinkist it produced 309 leads and 137 booked meetings in just over five months. Sharp copy only pays off if it lands. Ask how they handle cold email deliverability.
mgsh. is a Clay partner led by Stephanie Holland and Marina Ghilchik. It serves UK and EMEA scale-ups and treats revenue operations as part of brand strategy.
Stephanie brings brand consulting and Clay certification. Marina leads the Girls Who Clay community and previously ran global SDR teams at Talkwalker.
Work spans ICP scoring, TAM mapping, waterfall enrichment and CRM automation. Expect to budget above $10k a month, with a three-month minimum.
H2 is a UK-based Clay Solutions Partner with three services. It runs managed outbound, builds custom GTM systems and teaches private Clay workshops.
Research starts with your sales calls and past campaigns to find real buying triggers. Campaigns can go live in a day once the system is built.
Custom builds come with the runbook and training to operate them yourself. One client credits H2 with $4m in new pipeline.
StackOptimise is a London team of GTM engineers led by founder Felix Frank. It holds certifications across Clay, Smartlead and GetSales.
The entry offer is a free outbound trial that contacts 6,000 ICP leads. That lets you judge the targeting before signing anything.
Its case studies are specific. Hummingbird gained £2.1m in pipeline over ten months. BePro gained £5.4m in pipeline over nine months.
Clay is excellent at building and enriching lists. Turning those rows into multi-channel sequences at scale is where a retainer often creeps in.
Salesforge fills that gap for me. Its Clay integration pushes enriched rows straight into multi-channel sequences.
What GTM engineers actually build, with the full outbound setup shown inside Salesforge.
All the agencies on this list can run effective Clay outbound on your behalf. But if your goal is to own the process, control the data, and scale without growing headcount, Salesforge gives you the infrastructure to do it. Try the 14-day free trial - no credit card required.
Own the sending layer your Clay tables feed.
Try Salesforge free →14-day trial. No credit card required.
Or if you're still evaluating agency options, take a look at the certified Forge Experts for vetted agency partners.
| Agency | Location | Best For | Key Focus |
|---|---|---|---|
| B2B Boosted ✓ Forge Certified | United Kingdom | Owned Clay Systems | Clay Builds, Owned Systems |
| Vanderbuild ✓ Forge Certified | Warsaw, UK coverage | Signal-Based CRM Orchestration | CRM Automation, Signals |
| Growth Alliance ✓ Forge Certified | US & EU, remote | Scaling RevOps Infrastructure | RevOps, ABX Orchestration |
| Engineered GTM | London, UK | Proof-Before-Payment Builds | Owned Engines, First-Party Data |
| GTM Studios | London, UK | 30-Day Signal-Based Launches | Signals, ABM, RevOps |
| Fuelius | Six UK offices | HubSpot And Clay Together | HubSpot, Clay, Multi-Channel |
| Spring Drive | London, UK | Positioning-Led Outbound | Messaging, Outbound Architecture |
| mgsh. | London & remote | Brand-Led CRM Enrichment | CRM Enrichment, ABM |
| H2 | United Kingdom | Managed Outbound And Workshops | Managed Outbound, Training |
| StackOptimise | London, UK | Trial-First Outbound Pilots | Outbound Engines, Pilots |
The UK Clay scene is young but deep. The partners here range from founder-led labs to HubSpot Elite firms with six offices.
B2B Boosted, Vanderbuild and Growth Alliance are the three certified Forge Experts. Match the pick to your gap: owned builds, CRM orchestration or full RevOps architecture.
If the retainer maths does not work, run it yourself. Build lists in Clay, send through Salesforge and hire Agent Frank for ongoing prospecting.
Fourteen days is enough to know.
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