Jobs in Chelmsford, United Kingdom

We are seeking a highly skilled Data Scientist / Machine Learning Engineer to Join our client for a 3-month initial contract, with an immediate start. The role is Inside IR35 and offers a competitive day rate of £600–£700 DOE.

You will be working on a cutting-edge generative AI project, helping to integrate LLMs into complex, human-driven workflows. This is a remote role, though occasional travel to London, Sheffield, or Manchester may be required. The ideal candidate will have experience preparing data for LLMs and GenAI workloads, with strong technical ability in handling unstructured data and converting manual processes into structured, machine-readable formats.

Experience working with secure or sensitive datasets and existing active SC clearance is essential.

Key responsibilities include analysing and structuring messy datasets, engineering prompts, designing RAG datasets, and evaluating LLM outputs using a variety of metrics and methods. You will need to contribute independently and collaborate with a team of AI and data experts on fast‑paced, high‑impact projects.

Demonstrable passion for coding, data science, and open‑source technologies.

Active SC clearance and experience handling secure or regulated government data.

Proven ability to work independently and deliver high‑quality solutions with minimal guidance.

Excellent Python skills, including both exploratory scripting and production‑ready code.

Strong experience with exploratory data analysis and generating actionable insights.

• Deep understanding of data preparation for large language models, including:
  • Prompt engineering techniques.
  • Working with embeddings and vector databases.
  • Designing and optimising Retrieval‑Augmented Generation (RAG) datasets.
  • Evaluation methods such as retrieval scoring, LLM‑as‑a‑judge, and hallucination detection.

Ability to transform complex, unstructured data into structured formats suitable for LLM input.

Strong skills in data validation, anomaly detection, quality assessment, and documenting assumptions.

Clear and concise written and verbal communication skills for sharing technical findings.

Familiarity with AWS environments is a plus.

Flexibility to adapt to changing project requirements and a proactive mindset.

This is an excellent opportunity to work at the forefront of AI adoption in the public sector, making a tangible impact on critical government services. If you're passionate about machine learning, LLM technologies, and working with complex data challenges—this role is for you.