Four of the better-known unfair dismissal cases involve dismissals of employees for behaviour outside work. All four of those dismissals were held to be ‘fair’. This paper looks afresh at the subject matter of dismissals for behaviour outside work. It will argue, first, that employment tribunals should apply a separate framework to dismissals for behaviour outside work and not just apply the normal framework that is designed for dismissals for behaviour at work. Secondly, the paper will construct this separate framework to apply to dismissals for extramural behaviour. It will be argued that there should henceforth be a presumption that dismissals for behaviour outside work will be unfair unless the employer has a strong reason for thinking that the extramural behaviour of the employee will damage the business of the employer. The purpose of this paper is to suggest legal reasons for change to this area of unfair dismissal law as an addition to previously discussed normative reasons for change. In particular, the paper will develop the analogy between unfair dismissal cases on behaviour outside work and breach of personal confidence cases since the Human Rights Act 1998.