HR Manager

ONI

ONI

People & HR

Oxford, UK

Posted on Jun 2, 2026
Join ONI and Explore the Boundaries of Scientific Discovery!
At ONI, we are driven by a profound mission: to propel scientific discovery and combat diseases by granting everyone the ability to visualize, comprehend, and share the intricate microscopic details of life. Our revolutionary Nanoimager stands at the forefront of advancing cellular studies on a molecular level, making substantial contributions to the evolution of scientific knowledge.

We are seeking a HR Manager to deliver a robust, practical, and hands-on HR service across the UK, while supporting US-based managers and contributing to global HR projects. This role will manage the full employee lifecycle during a period of growth and change, ensuring operational excellence, compliance, and an outstanding employee and candidate experience.

As the HR Manager you will be responsible for:

    HR Operations & Employee Lifecycle

    • Oversee end-to-end HR operations across onboarding, offboarding, payroll coordination, and employee records management.

    • Ensure compliance with UK employment legislation and alignment where appropriate with US and European practices.

    • Implement and maintain clear, business-led HR policies and procedures, ensuring they are compliant, practical, and scalable.

    • Own and manage the HR tech stack (e.g. ADP, iHCM, Lever), including reporting, data integrity, and identifying opportunities to simplify and automate processes.

    • Maintain and audit accurate employee records and documentation in line with GDPR requirements.

    • Draft and manage employment contracts, letters, and HR documentation.

    • Administer UK benefits programmes, liaising with providers, payroll, and internal systems.

    Employee Relations & Advisory

    • Provide proactive guidance and coaching to functional leaders on organisational design, career frameworks, and performance management.

    • Support and upskill managers to effectively use HR tools and drive a high-performance, continuous improvement culture.

    • Manage and resolve complex employee relations cases, including disciplinaries, grievances, and investigations, ensuring fair and consistent outcomes.

    Talent Acquisition & Onboarding

    • Partner with hiring managers and the Talent Acquisition team to support end-to-end recruitment, particularly during peak hiring periods.

    • Contribute to candidate screening, interviewing, and stakeholder management.

    • Support the development and maintenance of a global library of job descriptions and person specifications.

    • Ensure a seamless pre-boarding and onboarding experience, working closely with hiring managers to deliver high-quality inductions.

    • Continuously improve recruitment and onboarding processes to enhance candidate and new starter experience.

    People Strategy & Projects

    • Provide input into remuneration and benefits strategy, including benchmarking and analysis where needed.

    • Support organisational design and workforce planning initiatives.

    • Contribute to global HR projects, ensuring alignment and consistency across regions.

Skills & Experience

    • Proven experience in a hands-on HR Manager or HRBP role, ideally in a scaling or international business.

    • Strong working knowledge of UK employment law and HR practices.

    • Experience managing employee relations cases end-to-end.

    • Exposure to talent acquisition and recruitment processes.

    • Experience working with HR systems (e.g. ADP, Lever or similar).

    • Strong organisational skills with the ability to manage both operational and strategic priorities.


At ONI, we understand that a fulfilling career involves more than just challenging work - it's about enjoying a well-rounded experience. When you become a part of our team, you not only contribute to groundbreaking research but also enjoy a range of benefits designed to enhance your life both inside and outside the workplace.
As an equal opportunity employer, we prioritize fairness and respect, ensuring every team member thrives regardless of their background. But that's not all - our perks include:
💰 Competitive Compensation We recognise and reward your talent. Enjoy a competitive salary that reflects your expertise and contributions, ensuring your hard work is recognized.
🌴 Time Off That Counts 28 days of annual leave plus bank holidays and 4 dedicated wellbeing days!
💪 Onsite Gym Facilities Stay active and energized with our convenient onsite gym, promoting your overall health.
🩺 Private Healthcare and Dental Coverage Your health matters to us. Access top-notch medical and dental services, ensuring your well-being is in good hands.
🤝 Inclusive Culture Be a valued member of our diverse, inclusive family. Your unique perspective is celebrated here, fostering a culture of mutual respect and understanding.
🧠 Health Assured Your mental health is essential. Access our comprehensive mental health support services for a balanced work-life experience.
🏦 People’s Pension Secure your future with our pension scheme, investing in your financial well-being beyond the workplace.
🎁 Perks at Work Enjoy exclusive discounts and deals through our perks at work program, adding value to your everyday life.
If you are driven by innovation, eager to make a significant impact in the realm of scientific and medical research, and possess the skills and passion we are looking for, we invite you to apply and be a part of our mission to improve our understanding of the details of life.