Conduct is a potentially fair reason for dismissal. Dismissals for misconduct are probably the most frequent category of unfair dismissal claim brought before the employment tribunal.

Dismissal for an isolated incident of misconduct will rarely be fair, although, in some circumstances, the incident will be sufficiently serious to justify dismissal for a first offence. Generally, dismissal for misconduct will only be a reasonable sanction if the employee has committed earlier acts of misconduct and been warned that further incidents may lead to dismissal. The misconduct for which an employee is dismissed need not be of the same nature as the conduct for which the warning was imposed. The courts have held that a final written warning always implies, subject only to the individual terms of a contract, that misconduct of any nature will often, and usually, result in dismissal.