Assistant Commercial Manager

Sizewell C is entering an exciting phase of growth as we mature into an independent organisation and continue building one of the UK’s largest and most important energy projects. We are now recruiting the below position.

Assistant Commercial Manager

Location: London, Manchester, Suffolk.

Contract: Permanent, full-time. 

What’s in It for You:

• Salary: Circa £47,000 er annum (depending on experience)

• Bonus: 5% annual incentive 

• Pension: Up to 7.5% employee / 15% employer contribution 

• Leave: 28 days holiday plus bank holidays 

• Hybrid Working: Typically, 2–3 days in the office per week, with flexibility based on business needs 

Closing Date: Wednesday 9th September 2026

Your Impact

Our Commercial Systems, Data, Governance and Performance team plays a key role in shaping how commercial systems, data and reporting support one of the UK's most largest and exciting infrastructure projects. As an Assistant Commercial Manager, you will be working alongside an experienced Commercial Manager and a diverse team of stakeholders to help support, develop and enhance our commercial systems, while delivering the reporting insights that are essential to successful project delivery.

This is a fantastic opportunity for someone with a background in commercial systems, reporting or data management who wants to broaden their experience within a major infrastructure programme. You'll gain exposure to large-scale procurement and commercial processes, influence how systems are used and developed, and work closely with stakeholders to improve data quality, governance and performance visibility. The role suits someone who enjoys solving problems, working with data, driving improvements and turning information into meaningful insight. You'll need strong attention to detail, the ability to prioritise effectively, and confidence communicating with a wide range of internal and external stakeholders.

With exposure to multiple systems, opportunities to influence future ways of working, and clear development potential, this role offers an excellent platform for building a long-term career in commercial systems, reporting and commercial management.

Accountabilities

• Work with internal teams, delivery partners and system specialists to support, maintain and continuously improve our commercial systems.
• Play a key role in system enhancements and new implementations, contributing to design, testing and deployment to ensure solutions meet business needs.
• Manage and coordinate system access and enhancement requests, helping to keep commercial processes running efficiently and maintaining strong controls.
• Develop and deliver engaging training materials that help teams understand and adopt commercial processes and systems.
• Lead responses to commercial performance and reporting queries, providing clear insights and support to a wide range of stakeholders.
• Collaborate with teams across the business to improve data management, reporting and performance visibility.

Organisation Chart

Reporting to Senior Commercial Manager – Systems, data and Performance.

Close relationship with 2 Commercial Managers.

Knowledge & Skills

Track record in building effective relationships with stakeholders,  influencing and presenting complex ideas confidently

Excellent written and verbal communications skills.

Good working knowledge of commercial end-to-end systems used throughout the contract lifecycle eg sourcing tools, contract management, ERP products

Good understanding of reporting tools and analytics, including developing and creating reports

Proven ability to engage senior leaders and stakeholders effectively.

Qualifications & Experience

The post holder should ideally hold graduate / post graduate qualification(s) related to Supply Chain or a similar professional discipline

A minimum of 3 years’ experience in a system / performance / data management role.

Demonstrated ability to develop and manage cross-functional relationships and understand and manage a complex portfolio of responsibilities.

Demonstrated success in delivering process and system improvements in support of broader business objectives.

Experience in working with commercial systems – tools covering activities like eSourcing  (Jaggaer) Purchase to Pay (SAP 4 HANA, Oracle) and Contract Management (CEMAR, Unifier)

Why Join Us  

• A major infrastructure project with national impact  
• Hybrid working with flexibility built in  
• Competitive salary, bonus and benefits  
• Clear progression and development opportunities  
• Supportive, collaborative team environment   

Behavioural Competences

Humility

• Recognise the value brought from different cultures and experiences.
• Be open to other’s points of view and ideas, be willing to debate and to compromise.

Positivity

• Positively challenge poor quality and performance.
• Identify solutions at the lowest possible level.
• Encourage others to bring new ideas forward.

Respect

• Value the rules and environment in which we operate.
• Give and receive feedback with respect.
• Embrace and engage with new people and ideas.

Solidarity

• One team, working closely together and helping each other.
• Empowered teams always looking forward.
• Shared responsibility for delivery the project outcomes.

Clarity

• Communicate clearly and consistently.
• Promote collaboration and team alignment.
• Clearer and faster decision making.
• Drive simplification at all levels.

If this sounds like the next step in your career, we’d love to hear from you. Apply today.