Principle AI Engineer | London

The Portfolio Group; Greater London; On-site; GBP 80,000 - 110,000; Full time

Job summary

A leading consultancy firm in London is searching for a Principal AI Engineer to lead the development of generative AI capabilities. The role involves designing and implementing advanced AI systems and RAG pipelines, collaborating with cross-functional teams, and providing technical leadership. Candidates should have strong Python skills and experience with RAG systems. This position offers a progressive opportunity to work at the forefront of AI model deployment with significant autonomy and support from a world-class leadership team.

Qualifications

• Strong Python expertise in production-grade AI development.
• Proven skills in building Retrieval-Augmented Generation systems.
• Practical knowledge of model adaptation techniques such as prompting.

Responsibilities

• Design, build, and train production-grade generative AI systems.
• Implement RAG pipelines using proprietary content.
• Collaborate with platform and product teams to transition AI capabilities into production.

Skills

Python proficiency

Experience with LlamaIndex

Experience with LangChain

Experience with LangGraph

Knowledge of RAG systems

Experience with model adaptation techniques

Understanding of generative AI evaluation

Technical design and delivery experience

Senior AI engineer experience

Job description

Job Title: Principal AI Engineer
Employer: The Portfolio Group
Location: London, United Kingdom
Salary:
Employment Type: Permanent
Reference Number: 23643_224544909

Job Details

Principal AI Engineer London Excellent Salary +Benefits

Join an award‑winning, internationally recognised International B2B Consultancy organisation as a Principal AI Engineer, where you will play a pivotal role in shaping and delivering production grade generative AI capabilities.

This is a senior; hands‑on engineering role focused on building the intelligence layer of advanced AI products. You will design and implement Retrieval‑Augmented Generation (RAG) pipelines, agentic workflows, and robust evaluation frameworks that ensure AI systems are accurate and aligned with real‑world business needs.

Reporting to the Director of AI, you will translate strategy and architecture into high‑quality implementations, working closely with AI Platform Engineering to ensure solutions are scalable, maintainable, and production ready.

Responsibilities

1. Design, build, and train production‑grade generative AI systems.
2. Implement robust RAG pipelines that effectively leverage proprietary and domain‑specific content.
3. Develop agentic and workflow‑based AI patterns with a focus on determinism, quality, and maintainability.
4. Apply model adaptation techniques prompting, fine‑tuning, distillation‑to optimise quality, latency, and cost.
5. Establish strong experimentation and evaluation practices to measure correctness, faithfulness, and robustness.
6. Act as a technical authority, providing hands‑on leadership, mentoring, and code‑level guidance to AI engineers.
7. Collaborate closely with platform, product, and delivery teams to move AI capabilities from experimentation into production.
8. Contribute to advanced retrieval techniques, including Graph‑RAG and structured knowledge representation, where they add value.

Required Skills & Experience

1. Strong Python proficiency for production‑grade AI development, with hands‑on experience using LlamaIndex, LangChain, and LangGraph.
2. Proven experience building Retrieval‑Augmented Generation (RAG) systems; Graph‑RAG experience is a plus.
3. Practical experience with model adaptation techniques, including prompting, fine‑tuning, instruction tuning, or knowledge distillation.
4. Solid understanding of evaluation and experimentation for generative AI, focused on correctness, faithfulness, and robustness.
5. Demonstrable experience owning technical design and delivery of complex AI, ML, or data‑driven systems in production environments.
6. Experience operating as a senior AI engineer or technical lead, balancing experimentation with production delivery and communicating effectively across teams.

This is a progressive career opportunity to work at the cutting edge of Generative AI model deployment, where your work directly shapes customer‑facing products and business innovation. You will have real ownership, technical autonomy, and the backing of a world‑class leadership team committed to building AI that delivers measurable value.