The Geotechnical Sub Alliance (GSA)

The Geotechnical Sub Alliance (GSA) is at the forefront of the Sizewell C nuclear power station development - one of the UK’s largest and most exciting infrastructure programmes.

We’re responsible for preparing the foundations of the entire site: designing and constructing cut-off walls, retaining structures, soil improvements and more. Using advanced geotechnical engineering and world-class construction technologies, this is a rare opportunity to contribute to a national project that will shape the UK’s clean-energy future.

The Role

The Senior Quantity Surveyor will play a key commercial role within the GSA, supporting the Managing Surveyor in delivering robust commercial governance, accurate cost management, and high-quality commercial intelligence across assigned work packages.

This role bridges responsibility between delivering commercial outputs directly and providing guidance to Quantity Surveyors within the team. The Senior QS will ensure effective contractual administration, maintain accurate forecasting, and proactively manage risk and opportunity to protect and enhance project value.

What You'll Be Doing

• Commercial & Cost Management: Manage commercial activities across work packages by ensuring effective cost control, accurate reporting and forecasting, subcontractor account management, and compliance with commercial procedures while supporting senior stakeholder reporting.
• Contract & Change Management: Administer NEC4 contracts by managing early warnings and compensation events, maintaining robust records, identifying and recording change, and providing commercial advice on contractual obligations and implications.
• Procurement & Supply Chain: Support procurement activities by developing tender documentation, evaluating and negotiating subcontractor agreements, monitoring supplier performance, and driving value for money through effective supply chain engagement.
• Project & Programme Support: Support project delivery by reviewing programme sequencing, enabling digital integration in commercial processes, and collaborating with cross-functional teams to align cost and programme objectives.
• Risk Management & Dispute Avoidance: Identify and mitigate commercial risks and opportunities, maintain strong supporting records, and assist in preparing evidence for claims and dispute avoidance in line with alliance standards.
• Team Support, Leadership & Development: Provide leadership and support to the commercial team through mentoring, reviewing outputs for accuracy, developing team capability, and fostering a positive and collaborative working environment.