The Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI), has set out how its prioritisation programme will affect the research projects in its Particle Physics, Astronomy and Nuclear Physics (PPAN) portfolio. Due to increased costs forecast in the future, the research council has conducted a prioritisation exercise for future projects to focus investment where it will deliver the greatest long-term impact and ensure STFC reaches a sustainable financial position. Protecting discovery researchSTFC will protect discovery research in particle physics, astronomy and nuclear physics, with the PPAN science budget decreasing by 2.7% over four years. Where projects are live, all will continue to the end of their current grant agreement without change, with outcomes relating to future funding. The strength of feeling and depth of engagement we have seen reflect the passion people have for the research STFC enables.