Senior Data Scientist

The John Lewis Partnership is the UK’s largest employee-owned business, where every Partner has a voice and a shared responsibility for our success. Within our Data, Insight & Analytics shared capability, we don’t just process information; we use it to power a happier world. We are looking for a proactive and creative Senior Data Scientist to join our team in London. In this role, you will be the bridge between complex data sets and actionable business strategy. Whether you are optimizing supply chains, refining product recommendations, or solving trading challenges, your mission is to help the Partnership make better, customer-centric decisions. This is a role for a Discipline Evangelist—someone who is as comfortable coding in Python as they are mentoring the wider data community and influencing senior stakeholders.

Salary: Up to £65,000

Location: London Head Office (Pimlico)

Working pattern/flexible working: Partners can work from home or the office, with a requirement for regular collaborative attendance at our head office locations.

Contract Type: Permanent

People Management: No direct reports, but significant mentoring responsibilities.

Key Responsibilities

• End-to-End Solution Development: Design and develop data science solutions from problem definition through to implementation and business adoption, balancing model complexity with business value.
• Model Building & Optimization: Transform complex data sets into models that optimize customer experience, revenue generation, and cost reduction.
• Stakeholder Influence: Act as a trusted partner to various business domains, translating technical concepts into clear, concise, and understandable recommendations for both technical and non-technical audiences.
• Technical Best Practices: Adhere to and champion best practices in SQL, Python, and Git within our tech stack (Snowflake, GCP, GitLab).
• Mentoring & Community: Advise and mentor the wider data and insight community on data science use cases, acting as a subject matter expert (SME).
• Governance & Ethics: Ensure all work complies with GDPR and adheres to the Partnership’s risk management and data privacy policies.
• Agile Collaboration: Work within multidisciplinary agile teams (ML Engineers, Analysts, Architects) to deliver data-driven products on time and within budget.

Essential Skills/Experience You’ll Need

• Machine Learning & Statistics: Proven experience applying statistical and machine learning techniques to solve real-world business problems.
• Python Proficiency: Expert user of Python and its relevant packages and libraries for data science.
• Data Manipulation: Strong SQL skills and the ability to link complex data sets for actionable insights.
• Communication & Influence: Excellent written and verbal communication skills, with a track record of working across functional teams to design technical solutions.
• Analytical Mindset: A highly analytical approach with a proactive "problem-solving" attitude.

Desirable Skills/Experience You May Have

• Sector Expertise: Previous experience in Retail, Marketing, or E-commerce.
• Modern Tech Stack: Familiarity with Cloud technologies (GCP/Snowflake) and command-line tools.
• Software Engineering & MLOps: Experience with the implementation of end-to-end ML solutions and Git version control.
• Agile Delivery: Experience working in Agile teams and applying Agile methodologies.
• Bayesian Modelling: Experience working with and implementing Bayesian statistical models in a commercial setting.

About The Partnership

We’re the largest employee owned business in the UK and home of our cherished brands, John Lewis and Waitrose. We’re not just employees, we’re Partners, driven by our purpose to build a happier world. As we look to our future, there’s never been a more exciting time to join us. We’re ruthlessly focused on being brilliant at retail. We continue to innovate, adapt and diversify. Never Knowingly Undersold on price, quality and service in John Lewis and passionately serving food-lovers in Waitrose. As Partners we all share the responsibility of ownership and in its rewards. We use our voices to contribute to our success, working together through the good and challenging times, holding true to our behaviours and treating everyone with kindness and respect. We all own making the Partnership somewhere we belong. Embracing our differences and creating an environment where we’re free to be ourselves and can THRIVE. Growing ourselves individually, and as a collective. As Partners, we make all the difference. And, we all own it.

Important notices

It’s important to note that some of our roles are subject to pre-employment vetting (which may include DBS checks for successful candidates). If required, you’ll be informed and provided with information about vetting during the recruitment process and we encourage you to complete any vetting documents quickly to avoid delays. Any DBS checks required will be carried out by a third-party registered body and financial probity checks may also be required for some of our roles. We occasionally close vacancies early in the event we receive a high volume of applications, and therefore, we recommend you apply early. If you require a reasonable adjustment due to a disability which means you may need longer to complete your application please contact us as soon as possible. We want all of our Partners to have a good work-life balance and we support flexible working. This might mean flexible or compressed hours, job sharing or shorter hour contracts, where possible. Please discuss this further with the hiring manager during your interview.