Genetic material was obtained from wild salmon fry captured from rivers adjacent to the escape event during surveys undertaken in 2020 and 2021 to examine if any hybridisation between the escaped fish and wild stocks had occurred. Using a panel of 74 Single Nucleotide Polymorphic markers the samples were examined to identify the presence of signatures of first generation (F1) hybrid fish (from crosses of wild and farm individuals). In Scotland, the prevalence of any existing F1 fish was determined in the 2020 cohort (2,358 samples), which could not have been influenced by the escape event. These levels were then compared to those in the 2021 cohort (2,586 samples), which could potentially be impacted by hybridisation from escapees from the event. For samples collected from rivers in Cumbria in the North of England during 2021, prevalence’s of F1 fish in fry (279 fish) were determined and compared to parr (58 fish), as no fry samples were available from 2020. The proportions of F1 fish were then compared between these age classes, with parr acting as a background estimate with which to compare the 2021 fry cohort.