A defendant’s surveillance evidence of the claimant on a personal injury claim may be allowed where it would substantially reduce the award of damages—so long as the claimant has not been ambushed, the High Court held in Hayden v Maidstone and Tunbridge Wells NHS Trust [2016] EWHC 1121 (QB). District Judge Stephen Gold, writing in NLJ this week, surveys the case and how the judge reached the decision.