Value streams for collected post-consumer textiles continue to be analyzed within the global challenge to develop and employ commercially viable, yet ethical and sustainable strategies within the fashion industry. Upcycling is an existing strategy applicable to fashion production, with discarded materials used to design and create higher value products, keeping them in productive use for longer. A number of very small, niche upcycling enterprises have emerged in the UK. These brands have succeeded in creating stylistically relevant and commercially successful fashion styles utilizing waste textile materials. The advantages of scaling these enterprises up are not only environmental, but also economic and social, thereby creating a sustainable and innovative business model for UK-led fashion production. Due to high levels of three key metrics of carbon, water and waste, UK government agency WRAP (Waste & Resources Action Programme) has identified textile products as priority materials for reuse and recycling. Upcycling enables a sustainable design option for reuse techniques to be employed for greatest economic and environmental benefit, in which used clothing and textiles are sourced for the production of newly designed fashion products. This paper identifies the key differences between standard fashion design and production processes and upcycled fashion design and production processes, in order to aid the development of large-scale fashion upcycling in the UK, and contribute to a circular economy.