This dataset contains exponential parameters from fitting an exponential curve to Delayed Flow Index (DFI or Characteristic Delay) curves using river discharge data from CAMELS-GB (Catchment attributes and hydro-meteorological timeseries for 671 catchments across Great Britain). The DFI curve at each catchment describes the response to rainfall over different time windows. The exponential parameters summarise the shape of the DFI curve at each site. Full details about this dataset can be found at https://doi.org/10.5285/d1df0a31-d329-4b21-8aa0-ba135d6a8042