Job Description Location: London Contract Type : Office-based, with hybrid working flexibility Working Pattern : Full time Closing date : Thursday 30th January 2026 Why Join Us? We’re building the future. Sizewell C is a once-in-a-generation infrastructure project that will power Britain’s energy security and net-zero ambitions for decades to come. Following our recent Final Investment Decision, construction is fully greenlit. This is your chance to be part of the largest investment in homegrown clean energy in decades, delivering low-carbon electricity to 6 million homes for at least 60 years. We’re looking for Commercial Assistants to help us deliver one of the UK’s most ambitious infrastructure projects. If you’re ready to make a meaningful impact, this is your opportunity. What’s in It for You Salary: Starting salary of £38,000 (depending on experience) Holiday: 28 days bank holidays Pension: Up to 7.5% employee / 15% employer contribution Flexible benefits & hybrid working options The Opportunity: Join a friendly, diverse, and high-performing team directly involved in Europe's biggest construction project - delivering a reliable, low-carbon energy supply for decades to come. By joining our Supply Chain Frameworks Team, as a Commercial Assistant you will play a key role in supporting the delivery of professional services contracts on one of the UK's most exciting infrastructure projects. Working closely with a Commercial Manager and the wider team, you'll gain hands-on experience in end-to-end contract management, stakeholder engagement, and commercial governance. This fast-paced role is perfect for someone who thrives on accuracy, prioritisation, and clear communication, while enjoying being part of a collaborative team that enables and supports both internal and external stakeholders. With exposure to multiple contracts and opportunities for progression, this is an excellent step for anyone looking to build a career in commercial management. Key Responsibilities • Support the Commercial Manager and team in managing professional services contracts from initiation to completion, including NEC/FIDIC/Bespoke framework agreements. • Assist with contract administration, including drafting, reviewing, and maintaining accurate documentation. • Manage Applications for Payment, ensuring timely processing and accurate records. • Prepare reports, trackers, and updates for senior management, including board-level documentation. • Prioritise tasks effectively to meet deadlines in a high-volume environment. • Support supplier relationship management across multiple framework contractors. • Assist with contract value tracking and budget monitoring. Skills & Attributes • Excellent communication skills and attention to detail. • Ability to build positive relationships with stakeholders at all levels. • A proactive approach and willingness to learn. • Strong organisational skills and ability to manage competing priorities. • Proficiency in Microsoft Office (Excel, Word, PowerPoint). • Degree in a relevant subject or working towards a commercial qualification (desirable). • Experience in a commercial, contract administration, or project support role (desirable). • Understanding of contract management principles (desirable). What We Offer • Exposure to end-to-end contract management and commercial processes on a major nuclear infrastructure project. • Opportunity to work with multiple stakeholders across professional services frameworks worth hundreds of millions. • A supportive team environment focused on collaboration and development. • Clear progression pathways for those seeking career advancement. 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 Key Competencies 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 tier 1s and 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 now and be part of something extraordinary.