AI has become the largest single destination for British venture capital. An HSBC Innovation Banking and Dealroom analysis found that UK AI startups raised $2.4 billion in the first half of 2025, a record 30% of all UK venture funding, and that London accounted for 68% of the 179 UK AI funding rounds tracked that year.
That concentration makes London the main European base for AI startups that are converting new rounds into new hires. This post is the London edition of Landbase's metro series and sits alongside the wider ranking of AI startups adding headcount fastest.
The list ranks venture-backed, AI-native startups headquartered in Greater London by 12-month headcount growth measured in Landbase data, then checks each company's funding and operating evidence against public sources.
How the companies were selected
The starting pool was venture-funded companies headquartered in London with more than 30 employees, narrowed to AI-native startups founded in 2019 or later.
Every company on the list had to meet four criteria:
- Headquartered in London, confirmed against company or press sources
- AI-native, meaning AI is the core of a commercially available product rather than a feature added to an older one
- Venture-backed, with at least one disclosed institutional round
- Positive 12-month headcount growth in Landbase data, used as the ranking order
Headcount growth is calculated from professional-profile data and can differ from company-reported figures, particularly for companies with contractors, expert networks, or teams that changed shape through a merger. Two companies with growth above 9,000% were excluded for that reason. Funding, valuation, and revenue figures below come from company announcements and press coverage rather than headcount data. Funding alone does not establish growth, so it is treated as one of several company buying signals.
1) Throxy
Co-founder: Pablo Jiménez de Parga Ramos
Latest round: $6.2 million seed, September 2025
12-month headcount growth: +842%
Category: AI outbound sales
What Throxy builds
Throxy runs fully managed outbound prospecting for B2B companies in traditional sectors such as manufacturing, logistics, and medical equipment. It combines AI research and targeting with its own outbound operation, and clients pay when qualified meetings are booked rather than paying a fixed retainer.
Latest growth evidence
When it announced its seed round, Throxy reported about $1.5 million in annual recurring revenue with a team of three and said it planned to grow headcount nearly fivefold. VentureBeat described the company as challenging larger AI sales platforms with a pay-per-meeting model.
Recent funding
Base10 Partners led the $6.2 million seed, with participation from Y Combinator (Spring 2025 batch).
Why it matters
Throxy shows that London's AI sales category includes outcome-priced services, not only software, and that buyers outside the tech sector are adopting AI-led outbound.
2) Jack & Jill
CEO: Matt Wilson
Latest round: $40 million Series A, September 2026
12-month headcount growth: +658%
Category: AI recruiting agents
What Jack & Jill builds
Jack & Jill uses two AI agents on opposite sides of the hiring market. Jack works for candidates, learning what they want through voice calls, email, and WhatsApp. Jill works for employers, reading job descriptions and questioning hiring managers about what success in a role looks like.
Latest growth evidence
The company reported that Jack's candidate network had reached 350,000 people, up tenfold since its seed round, and that Jill served about 5,000 businesses, including Ramp, Attio, and Multiverse. It said it had arranged 25,000 interviews in total and was adding about 5,000 a month, alongside a reported 40-fold increase in revenue since the seed.
Recent funding
Air Street Capital led the $40 million Series A, with Madrona and Antler joining and Creandum, Ada Ventures, and Entrepreneurs First returning. Total funding is about $60 million, including a $20 million seed in October 2025.
Why it matters
Jack & Jill is one of the fastest-scaling AI recruiting companies founded in 2025, and its U.S. expansion makes it a London export rather than a domestic tool.
3) Nscale
CEO: Josh Payne
Latest round: $2 billion Series C, March 2026
12-month headcount growth: +542%
Category: AI compute infrastructure
What Nscale builds
Nscale builds and operates GPU data centers and the software layer that runs AI training and inference on them.
Latest growth evidence
Nscale filed for a New York Stock Exchange listing in September 2026. Its filing showed first-half 2026 revenue of $140.6 million, up from $10.4 million a year earlier. The company reported $103.4 billion in contracted deals as of August 31, 2026, including a reported six-year compute agreement with Anthropic, according to coverage of its IPO filing.
Recent funding
Aker ASA and 8090 Industries led the $2 billion Series C at a $14.6 billion valuation, with Nvidia and Dell among participants. It followed a $1.1 billion Series B in September 2025.
Why it matters
Nscale is the London AI startup with the largest capital base, and its growth depends on a small number of very large compute contracts rather than on many smaller customers.
4) Covecta
CEO: Scott Wilson
Latest round: $6.5 million seed, September 2025
12-month headcount growth: +400%
Category: AI agents for lending and credit
What Covecta builds
Covecta builds AI agents for banks, lenders, and other financial institutions. The agents handle front-line lending and credit tasks that relationship managers and analysts usually do by hand.
Latest growth evidence
Covecta's first major client was Metro Bank, which reported a 60–80% reduction in task completion times after adopting the platform, according to Fintech Futures.
Recent funding
Salesforce Ventures led the $6.5 million seed. It followed a pre-seed of more than £1 million raised from industry veterans and angel investors.
Why it matters
Covecta targets one of London's largest local buyer groups, UK banks and lenders, with an agent product built for regulated credit workflows.
5) Poindexter Labs
CEO: Jocelyn D'Arcy
Latest round: £2 million seed, June 2026
12-month headcount growth: +389%
Category: Expert AI training data
What Poindexter Labs builds
Poindexter Labs produces expert-level reasoning data for training advanced AI models. Its contributors are mathematicians and scientists who create and review the problems and solutions that frontier labs use to improve model reasoning.
Latest growth evidence
The company said it reached about $1.6 million in revenue in its first six months, before raising outside capital, and that its raise coincided with its first direct contract with a major frontier AI lab, according to coverage of the seed round.
Recent funding
Episode 1 led the oversubscribed £2 million seed, with Octopus Ventures' First Cheque Fund, angel investors, and several of the company's own expert contributors participating.
Why it matters
Poindexter Labs draws on London's university and quantitative talent pool to supply a scarce input for frontier model development.
6) Conduct
CEO: Jan-Philipp Haas
Latest round: $60 million Series A, June 2026
12-month headcount growth: +343%
Category: Agentic AI for enterprise IT and SAP
What Conduct builds
Conduct describes its product as an AI operating system for enterprise software, starting with SAP. It reads custom code, maps dependencies, automates development and deployment work, and speeds up migrations such as moves to SAP S/4HANA.
Latest growth evidence
In May 2026 Conduct said it had been recognized as a strategic AI partner for SAP Cloud ERP transformations and named Heidelberg Materials, Daimler Truck, Fraport, and DHL as joint customers. A month later it raised a $60 million Series A with a strategic investment from SAP.
Recent funding
Index Ventures and ICONIQ co-led the Series A, with existing investors Creandum, Lucid Capital, and Booom participating.
Why it matters
Conduct, founded by former Palantir executives, targets the large services budgets attached to ERP modernization rather than new software spend.
7) Finster AI
CEO: Sid Jayakumar
Latest round: $15 million combined seed and Series A, October 2025
12-month headcount growth: +194%
Category: AI for investment banking and asset management
What Finster AI builds
Finster AI provides an AI platform for investment banks and asset managers. It helps teams draft investment memos, run market research, assemble client materials.
Latest growth evidence
Finster said it had early partnerships with tier 1 global investment banks and asset managers. It planned to use its funding to expand into New York and grow its London headquarters.
Recent funding
FinTech Collective led the Series A portion and Peak XV led the seed, with Hoxton Ventures continuing to invest.
Why it matters
Finster pairs DeepMind research experience with the City's banking customer base, a combination that recurs across London's AI finance startups.
8) Scope
CEO: Jonathan Low
Latest round: $20 million, May 2026
12-month headcount growth: +169%
Category: AI for industrial inspection
What Scope builds
Scope builds AI software for the testing, inspection, and certification industry. Inspectors use it to capture findings in the field and produce inspection reports.
Latest growth evidence
Scope reported 9x ARR growth and a 100% pilot conversion rate since launching in July 2025, and said inspectors at six of the world's top 10 inspection companies use the platform. Details appear in to coverage of its $20 million raise.
Recent funding
Index Ventures led the $20 million round, reported as a Series A, with Susa Ventures and Entrepreneurs First participating.
Why it matters
Scope is an example of vertical AI aimed at field workers in an industry with large, fragmented service providers.
9) Electric Twin
CEO: Alex Cooper
Latest round: $10 million, February 2026
12-month headcount growth: +160%
Category: Synthetic audiences for market research
What Electric Twin builds
Electric Twin builds synthetic audiences, simulated models of a company's customers built from its own survey data, focus groups, and interviews. Clients use them for concept and pricing tests.
Latest growth evidence
The company reported nearly 40,000 evaluations across 155 countries when it announced its funding. In April 2026, The Times announced a synthetic audience tool built on Electric Twin, according to the company's funding announcement.
Recent funding
Atomico led the $10 million round, with LocalGlobe, Mercuri, and Marc Andreessen participating. It followed a $4 million pre-seed, for total funding of $14 million.
Why it matters
Electric Twin competes for traditional market research budgets, one of several London categories where AI is replacing a service rather than adding a tool.
10) Stacks
CEO: Albert Malikov
Latest round: $23 million Series A, February 2026
12-month headcount growth: +143%
Category: Agentic AI for accounting and financial close
What Stacks builds
Stacks provides an accounting workspace where enterprise finance teams and AI agents handle reconciliations, intercompany matching, accounts receivable, cash application, and reporting. Staff approve the agents' work before it posts to the ERP.
Latest growth evidence
Stacks reported more than 30 enterprise customers in under a year after leaving stealth, including Nivoda and Epidemic Sound, and said its platform saves more than 100,000 finance hours a year. Nivoda reported an eight-day shorter monthly close and 95% of reconciliations automated, according to the Series A announcement.
Recent funding
Lightspeed led the $23 million Series A, with EQT Ventures, General Catalyst, and S16VC investing again. Earlier seed funding was led by EQT Ventures and General Catalyst.
Why it matters
Stacks is one of three companies on this list selling AI into finance functions, which reflects how much of London's AI demand comes from financial services.
What the London AI startup market shows
Several patterns stand out.
First, finance is the largest single category. Covecta sells to lenders, Finster AI to investment banks and asset managers, and Stacks to corporate finance teams. Each sells into regulated workflows where accuracy and review matter.
Second, funding is highly concentrated. Nscale's $2 billion Series C is more than ten times the combined value of the latest rounds at the other nine companies, while Throxy, Covecta, and Poindexter Labs are growing quickly on seed rounds below $10 million.
Third, the city's research talent shows up in the founding teams. Finster AI's founder spent seven years at Google DeepMind, Conduct by former Palantir executives, Poindexter Labs relies on mathematicians and scientists, and Electric Twin works with London School of Economics researchers.
For GTM teams, these companies combine new funding with rapid hiring and, in several cases, U.S. expansion. That combination is more useful when paired with hiring, leadership, technology, and data enrichment signals than when funding is viewed on its own. Teams researching related categories can compare this list with Landbase's rankings of AI fintech startups hiring fastest and AI sales startups hiring fastest, the European comparison of Paris AI startups hiring fastest, and the full set of AI startups hiring fastest by city.
How Landbase supports London AI startup account research
The ranking in this article was built with Landbase. A natural-language search identified venture-funded companies headquartered in London, an enrichment step added founding year, headquarters city, and 12-month headcount change, and the results were filtered and sorted into a structured dataset.
Landbase's web and CLI interfaces access the same account, datasets, and saved work.
For more complex requirements, the Advanced Dataset Creator supports filters, calculations, and custom output fields.
Landbase's data infrastructure includes more than 800 million contacts and more than 40 million companies across more than 1,500 fields, with enrichment from more than 20 providers.
A London workflow could, for example, identify AI startups headquartered in Greater London that raised a seed or Series A round in the past year, doubled headcount, sell to financial services firms, and recently opened a New York office or hired a U.S. sales leader.
The Landbase CLI setup supports these workflows from a standard terminal and from AI coding environments including Claude Code and Codex.
Frequently Asked Questions
Which AI startups in London are growing fastest?
Based on 12-month headcount growth in Landbase data, the fastest-growing venture-backed AI startups headquartered in London include Throxy, Jack & Jill, Nscale, Covecta, Poindexter Labs, Conduct, Finster AI, Scope, Electric Twin, and Stacks. Each grew headcount by more than 140% over the past year.
Which London AI startup grew headcount fastest?
Throxy, an AI outbound sales company, recorded the highest 12-month headcount growth among companies that met this list's criteria, at more than 800%. Jack & Jill and Nscale followed, each above 500%.
Why is London attracting AI startups and AI hiring?
London combines a large share of UK AI venture funding, research talent from universities and labs such as Google DeepMind, and a dense base of financial services, media, and enterprise buyers. HSBC Innovation Banking and Dealroom found that London accounted for 68% of UK AI funding rounds tracked in 2025.
Does headcount growth mean a London AI startup is growing quickly?
Not on its own. Headcount data can differ from company figures and fast hiring does not guarantee revenue growth. This list therefore pairs headcount growth with disclosed funding, revenue, customer, and valuation evidence wherever it is available.
How can GTM teams find fast-growing AI startups in London?
Teams can start with a headquarters and category definition and then filter by headcount growth, funding stage, recent rounds, target buyer, and hiring activity. Landbase can combine these criteria into reusable datasets and return company and contact information through web and CLI workflows.
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