I believe the evidence of lions being used in executions in Britain is flimsy. Nevertheless, this image of a lion on an elaborate key found in Leicester is interesting:   https://www.miragenews.com/thrown-to-lions-new-evidence-from-roman-britain-609741/ https://www.kcl.ac.uk/news/thrown-to-the-lions-new-evidence-from-roman-britain-executions-revealed