Machine Learning Researcher

Arcus Search; Greater London; Hybrid; GBP 120,000 - 190,000; Full time

Job summary

Arcus Search is seeking a Principal Machine Learning Scientist for our London-based client. This hybrid role blends hands-on ML with architectural leadership to shape scalable, intelligent systems powering personalised user experiences.

You will lead ranking, retrieval, and recommendation efforts, drive production pipelines, and push advances in representation learning and embeddings at scale. A PhD/MSc and a proven track record of leading complex ML initiatives are expected.

Qualifications

• Experience in ML or Applied Science with emphasis on scalable ML systems.
• Strong track record from research to production in ML systems.
• Deep expertise in recommendation, ranking or retrieval.
• Expertise in representation learning and embedding techniques.
• ML system design at scale with large datasets.
• Advanced degree in ML, CS or related field; leadership of complex initiatives.

Responsibilities

• Design and scale ML systems powering personalised user experiences.
• Lead on ranking, retrieval and recommendation tasks at scale.
• Build production ML pipelines and real-time inference.
• Advance representation learning and embedding methods.
• Architect large-scale ML platforms and data processing pipelines.
• Drive experimentation, optimization and model performance.
• Provide technical leadership across ML and engineering teams.

Skills

Recommendation systems

Ranking

Retrieval

Representation learning

Embeddings

ML system design

Production ML pipelines

Big data (Spark)

Technical leadership

Education

MSc or PhD in Machine Learning / CS

Tools

Spark

Job description

Principal Machine Learning Scientist | London | Hybrid

I'm working with a leading global technology company looking to hire a Principal Machine Learning Scientist into a growing ML organisation in London.

This is a senior, hands-on role focused on designing and scaling machine learning systems that power personalised user experiences and intelligent decision-making across a large-scale platform.

What you'll be working on

• Ranking, retrieval and recommendation systems
• Representation learning and embeddings
• Large-scale ML architecture and system design
• Production ML pipelines and real-time inference
• Experimentation, optimisation and model performance
• Big data technologies including Spark
• Technical leadership across ML and engineering teams

We're looking for people with

• Experience in Machine Learning or Applied Science
• Strong experience building ML systems from research through production
• Deep expertise in recommendation systems, ranking or retrieval
• Representation learning and embedding techniques
• ML system design at scale
• Experience working with large, complex datasets
• MSc or PhD in Machine Learning, Computer Science or a related field
• A track record of leading complex technical initiatives

We're hiring across multiple senior ML positions, so there's also interest in exceptional candidates at Senior Machine Learning Scientist level.

If you're working on large-scale recommendation, search or ranking problems and are open to hearing about a new opportunity, I'd be happy to share more.