Senior Research Scientist (Must be based in UK)

Entrepreneur First; London; Hybrid; GBP 80,000 - 110,000; Full time

Job summary

A leading technology firm in London is seeking a Senior Research Scientist. You will lead innovative projects on large language models and drive advancements in dialogue systems, integrating them into customer service applications. Candidates should have a PhD, over 5 years of experience in deep learning, and expertise in Python. The role offers competitive compensation, flexible working options, and other unique benefits.

Benefits

Equity options

Flexible working from home policy

Company-funded healthcare and dental cover

Gym discounts

Mental health programs

Qualifications

• 5+ years of hands-on experience in deep learning.
• Proven track record of research innovation, including published work or deployed systems.
• Demonstrated expertise in reinforcement learning, conversational AI, or related domains.

Responsibilities

• Lead and execute complex research projects with clear business impact.
• Design and implement novel post-training strategies like preference tuning.
• Conduct empirical studies to assess model performance in deployments.

Skills

Deep learning

Python programming

Natural Language Processing

Reinforcement learning

Conversational AI

Education

PhD in Machine Learning or related field

Tools

PyTorch

Job description

Overview

Senior Research Scientist based in the United Kingdom. London, United Kingdom. PolyAI automates customer service through lifelike voice assistants that let customers lead a conversation. Our voice assistants enable businesses to deliver outstanding customer service that rivals human agents. Our customers, including leading brands, are expanding how they use our platform, driving automation of critical customer service operations and integrating PolyAI into daily workflows.

We are looking for a Senior Research Scientist to join our world-class team and lead cutting-edge work on large language model (LLM) post-training. This role focuses on building the future of dialogue systems with novel approaches to reasoning, reinforcement learning, audio-first LLMs, and more.

As a Senior Research Scientist at PolyAI, you’ll lead impactful research projects from ideation through deployment, driving innovation in how we train and adapt LLMs for real-world conversations spanning voice, text, and multimodal contexts.

Responsibilities

• Lead and execute complex research projects with clear business impact.
• Design and implement novel post-training strategies including preference tuning, reward modeling, and synthetic supervision.
• Develop innovative model architectures and training approaches for conversational AI, including speech-aware and multimodal models.
• Conduct empirical studies to assess model performance in live deployments and iterate quickly based on real-world data.
• Generate, collect, and annotate training data—including synthetic and real-world conversational datasets—with attention to quality and bias mitigation.
• Design robust evaluation metrics and benchmarks for LLM-based assistants in customer service domains.
• Work closely with engineering and product teams to integrate research into production environments.
• Collaborate with legal and compliance teams to ensure responsible use of data and models.
• Stay current with academic and industry advances in LLMs, ASR, TTS, RLHF, and multimodal learning.

Requirements

• PhD in Machine Learning, Natural Language Processing, Computer Science, or a related field.
• 5+ years of hands-on experience in deep learning.
• Proven track record of research innovation, including published work or deployed systems.
• Strong programming skills in Python and deep learning frameworks like PyTorch.
• Demonstrated expertise in at least one domain area such as reinforcement learning, conversational AI, audio modelling, or LLM alignment.
• Experience leading projects end-to-end, from ideation to deployment.
• Excellent communication skills with the ability to write clear technical documents and explain complex concepts to diverse audiences.
• Comfortable working in ambiguity and driving clarity through experimentation and data.

Preferred Qualifications

• Experience with speech technologies such as ASR and TTS.
• Familiarity with cloud environments (AWS, GCP, Azure).
• Exposure to RLHF, reward modelling, or human preference data collection.
• Prior work on real-time systems, streaming inference, or memory-efficient model deployment.

Benefits and Culture

• Competitive compensation based on experience, expertise, and responsibility, with equity options.
• Flexible working from home policy and the option to work from outside the UK for up to 6 months each year.
• Employee share options plan and learning and development allowance.
• Company-funded fertility and family-forming programmes, private healthcare and dental cover, gym discounts, and access to mental health programs.
• One-off WFH allowance to improve comfort and focus.
• Other support programs including TELUS Health EAP and a values-driven culture committed to inclusion and excellence.

Values

• Only the best – We hire and nurture excellence.
• Ownership – We take responsibility for initiatives and outcomes.
• Relentlessly improve – We continuously evolve to transform conversational AI.
• Bias for action – We move quickly and deliver impact.
• Disagree and commit – We work through disagreements and align on decisions.
• Build for people – We design for a future that embraces automation.

PolyAI is an equal-opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. All employment decisions are based on business needs without regard to ethnicity, religion, sexual orientation, gender identity, family or parental status, national origin, neurodiversity status, or disability status.