Senior LLM Engineer – London | Hybrid (2 days per week on-site, Bank area)
My client is a long-established consultancy that originally built its reputation in data engineering and wider data transformation, and over the past few years has grown a strong applied AI practice. They tend to work with UK organisations where data security, reliability and explainability actually matter, so think regulated, risk-aware, or operationally critical environments rather than hype-driven MVPs.
The current AI/ML group is around eight senior engineers, with backing to grow sensibly (not a hiring spree). This role sits within that team and is focused on designing and deploying LLM systems that make it into production, are cost-efficient, and work reliably in the real world.
What you’ll be doing:
• Owning the design and build of LLM-based systems end-to-end
• Fine-tuning and adapting models (LoRA, instruction tuning, PEFT etc) rather than just prompt-engineering
• Building RAG workflows, embedding strategies, memory layers and domain grounding
• Working out how to measure output quality, reduce hallucination risk and improve robustness
• Optimising inference performance (quantisation, distillation, pruning, batching, caching)
• Deploying models into production environments where latency, cost and privacy are real constraints
• Working closely with both internal engineers and client teams to ensure what gets built actually lands well
What they’re looking for:
• Hands-on LLM experience beyond prototyping / notebooks
• Strong Python and experience with PyTorch / Hugging Face / similar tooling
• Experience deploying models into production (not just training them)
• Familiarity with vector stores and RAG patterns
• Comfortable operating in a hybrid environment and speaking with stakeholders where required
• Someone who enjoys solving real problems end-to-end: from understanding the domain → designing the approach → shipping the implementation
• Experience of MLFlow / MLOps highly desirable
Important notes (just to be upfront):
• They cannot sponsor visas, so you’ll need existing right to work in the UK
• No relocation support – you’ll need to already be UK-based and able to be in London (Bank area) twice a week
• This is a senior role – typically someone with 3+ years’ experience in ML/AI roles, ideally from a data science or applied ML background
Benefits / set-up:
• Modern kit (MacBook etc.)
• 27 days annual leave + bank holidays
• 4-week paid sabbatical after 4 years’ tenure
• Regular team meet-ups, workshops, and knowledge-sharing sessions
• Sensible working hours – grown-up environment, not crunch culture
• Clear progression as the AI group continues to scale
• Stable team, low-ego culture, and work that isn’t just slideware or demos
