About 1.3 million heart valve replacements are undertaken each year worldwide; this number is estimated to increase 4-5 times by 2050 due to population aging. Prosthetic heart valves currently used in clinical practice, either biological or mechanical, are imperfect. Biological valves are made from animal tissue sutured by hand on rigid frames, and they have a limited durability of only 10-12 years. Mechanical valves are often used in younger patients as they last longer, but they require life-long anticoagulation with warfarin, which significantly affects patients' quality of life, triggers teratogenicity during pregnancy and causes 3-4% thrombo-embolic/haemorrhagic events/year. We have developed the next generation heart valve prosthesis; our innovative polymeric heart valve combines excellent durability and hemocompatibility, ensuring a long-lasting implant without the need for anticoagulation. Our valve represents the ideal treatment for patients of all age, while reducing healthcare costs in terms of repeated surgeries, hospital readmissions, medication management etc. We have already tested prototype valves in the lab in Cambridge, in equipment simulating the operation of a real heart, and demonstrated hydrodynamics equivalent to best in class biological valves, combined with durability in excess of one billion cycles (equivalent to 25 years of use in a human) in accelerated bench testing. A small acute trial in three sheep has also been performed in Bristol, demonstrating that the valve is easy to stitch in, and shows no mechanical failure, no trans-valvular regurgitation, low trans-valvular pressure gradients, and good biocompatibility and blood compatibility.