This dataset provides a coherent, quality-controlled collection of 15-minute river flow observations from across the United Kingdom. It brings together more than 1,300 gauging stations and over 50,000 station-years of data collected by the main UK measuring authorities - the Environment Agency (England), Scottish Environment Protection Agency, Natural Resources Wales, the Department for Infrastructure (Northern Ireland), and the UK Centre for Ecology & Hydrology. The records span from 1948 to the present day and represent the first national-scale compilation of sub-daily flow data in a consistent format. The dataset was created by assembling raw hydrometric records from open APIs and data requests to measuring authorities, then standardising them to a uniform 15-minute time step. A structured quality control framework was applied to identify and flag potential issues such as missing or duplicated values, irregular time steps, and implausible flow events. Each record includes a detailed quality code indicating the outcome of these checks, and a suite of accompanying metadata files provides full traceability of data provenance, quality control results, and any adjustments made during processing. The resource is designed to support large-sample and national-scale hydrological research, particularly for applications requiring high-resolution data such as flood analysis, catchment response studies, and model calibration. Full details about this dataset can be found at https://doi.org/10.5285/211710ac-f01b-4b52-807f-373babb1c368
