Defra is seeking to contract with supplier(s) possessing the scientific, technical and analytical expertise required to provide baseline measurements of stratospheric ozone and ultraviolet radiation. The successful supplier(s) will undertake daily column ozone observations and collect spectral UV-B measurements across the United Kingdom’s three ozone monitoring sites in Manchester, Reading and Lerwick. The service will include quality assurance and quality control, calibration checks, comparison of ozone and ultraviolet observations with satellite data and nearby ground-based observations, maintenance of running 20-year climatology for each dataset, and submission of data to relevant national and international institutions. The outputs will support the continuity of the United Kingdom’s long-term ozone monitoring record, annual reporting, environmental monitoring and the United Kingdom’s obligations under the Vienna Convention. We are envisaging that the new contract will start on 18 May 2027 and run for five years. We estimate the total contract value to be up to £1.7 million excluding VAT. These details are indicative and remain subject to market engagement, affordability, internal approval and applicable procurement requirements.