Commercial Assistant in Leiston

Sizewell C’s business is to design, finance, construct, commission, operate, maintain, and eventually decommission the nuclear power plant and related infrastructure at Sizewell C in Suffolk. Overall, whilst the Company is in the construction phase, the Boards’ principal focus is on the development and construction of Sizewell C on time, on budget and to the highest quality and safety standards. The Company is maturing to meet all these requirements.

Sizewell C is economically regulated by OFGEM under the Regulated Asset Base (RAB) model similar to other UK electricity distribution networks and Thames Tideway. Sizewell C construction strategy is to replicate the design of Hinkley Point C, using the majority of the same supply chain, but innovating in the way it is delivered to achieve savings in time and cost of around 20%. The CCO will need to be guided by and incorporate lessons learned from the Hinkley Point C commercial delivery to achieve Sizewell C’s ambition.

Following Financial Completion and Revenue Commencement, Sizewell C is fully funded and is owned by The Secretary of State for Energy Security and Net Zero representing HM Government, La Caisse, Centrica, EDF and Amber Infrastructure. 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: Commercial Assistant Contract: Permanent, full‑time

What’s in It for You

• Salary: Competitive, depending on experience
• Bonus: 5% annual incentive
• Pension: Up to 7.5% employee / 15% employer contribution

The Opportunity

Kick‑start your commercial career on one of the UK’s most significant infrastructure projects. You will be joining the SZC Site Delivery Commercial Team as a Commercial Assistant and play a vital role in supporting the delivery of the Site Delivery scope on a landmark nuclear project. This is a fantastic opportunity to gain real, hands‑on experience within a high‑performing commercial environment, working alongside experienced Commercial Managers and a collaborative, supportive team. You’ll be at the heart of contract administration and governance, supporting day‑to‑day commercial activities while developing the skills and exposure needed to progress your career. If you’re detail‑oriented, proactive, and enjoy working in a fast‑paced, team‑focused setting, we’d love to hear from you.

What You’ll Be Doing

• Supporting the Commercial Managers with contract administration, ensuring documentation is accurate, compliant, and well maintained
• Managing Applications for Payment, supporting timely processing and maintaining clear audit trails
• Preparing reports, trackers, and senior‑level updates
• Prioritising and managing multiple tasks to meet deadlines in a high‑volume environment
• Supporting supplier and stakeholder relationships
• Assisting with compliance reporting

What You’ll Bring

• Strong communication skills with excellent attention to detail
• The confidence to build effective working relationships with stakeholders at all levels
• A proactive mindset with a genuine willingness to learn and develop
• Excellent organisational skills and the ability to juggle competing priorities
• Proficiency in Microsoft Office, particularly Excel, Word, and PowerPoint
• Previous experience of contract management systems (Unifier, CEMAR, SAP) desirable but not essential

Why Join Us

• A major infrastructure project with national impact
• Supportive, collaborative team environment
• Hands‑on exposure to end‑to‑end contract management on a major UK nuclear infrastructure project
• The opportunity to work on a multi‑billion‑pound contract
• Clear progression pathways for individuals looking to build a long‑term career in commercial management

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. One team, working closely together and helping each other. Empowered teams always looking forward. Shared responsibility for delivering the project outcomes.
• Clarity: Communicate clearly and consistently. Promote collaboration and team alignment. Drive simplification at all levels.

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

When joining Sizewell C, you may wonder why you are contacted by colleagues with an EDF email or see the EDF logo on portals that you access and/or documentation you receive; this is because we have partnered with EDF for the provision of a number of support services whilst we complete a successful transition out of the EDF group. At Sizewell C we encourage and embrace diversity and how it can improve our experience and performance at work. It is a requirement that those who join us have the right to work in the UK. Whilst sponsorship may be a possibility that we can explore, we are fully committed to local recruitment where possible, and those already holding the right to work in the UK. To be appointed to this role, you will need to meet the criteria for Security Vetting, which will, ordinarily, require you to have been a resident of the UK for at least three of the past five years.