Cement is the backbone of modern construction, but it comes at a heavy environmental cost. The production of Portland cement clinker (CEM I) is responsible for around 7% of global carbon dioxide emissions, making it one of the biggest single sources of industrial greenhouse gases. Reducing the amount of clinker used in cement and concrete is one of the most effective ways to cut the embodied carbon of buildings and infrastructure. Current approaches rely on adding materials such as ground granulated blast furnace slag (GGBS) or pulverised fuel ash (PFA), but supplies of these are increasingly limited. New alternatives like calcined clays or alkali-activated cements (AACMs) show promise, but uptake of these materials has been hampered supply constraints, regulatory limits, and in some cases reduced performance. Reclinker offers a new solution. By recycling construction and demolition waste (CDW) and upcycling electric arc furnace (EAF) slag, Reclinker creates a recycled cement clinker that can replace up to 50% of the Portland clinker fraction in a cement mix. This dramatically reduces carbon emissions while turning low-value waste streams into high-value building materials. Unlike many alternatives, Reclinker can also be used alongside traditional SCMs, unlocking even greater carbon savings. This project will deliver the world's first operational demonstration of circular cement. Around 2,000 tonnes of waste concrete washout from EDF's Hinkley Point C (HPC) construction site will be processed into EAF flux and used in four 24-hour production runs at 7 Steel's EAF facility in Cardiff. The resulting recycled cement will be tested in real concrete applications. Independent organisations will verify that the product meets the rigorous performance requirements of UK and European standards. A full Life Cycle Assessment will measure the environmental benefits, which are expected to show over 50% CO₂ savings compared to conventional cement. The project is led by Reclinker Ltd, a UK start-up specialising in low-carbon construction materials. By verifying that recycled cement works at industrial scale, the project will de-risk the technology, build customer confidence, and pave the way for rapid market adoption. In the future, scaling this innovation across the UK cement sector could save millions of tonnes of CO₂ every year while creating a replicable model for export worldwide. This will help position the UK as a leader in circular, resource-efficient construction materials with the opportunity to serve a £20bn addressable market globally.