Gross misconduct is misconduct that is so serious as to justify dismissal without notice. What amounts to gross misconduct will depend on the circumstances of the employer but would include theft, fraud and violence.
In a recent case, the Employment Appeal Tribunal (EAT) considered whether it was fair to dismiss an NHS consultant who had undertaken private work whilst signed off sick and receiving full sick pay from her NHS post. The EAT held that, although it was reasonable to treat the consultant's conduct as gross misconduct, it was not reasonable to jump to the immediate conclusion that the consultant should be dismissed. In such circumstances, the employer must still consider whether there are any mitigating circumstances. These might include the employee's position, their length of service and their disciplinary record. Only once the employer has considered these factors can they assess whether dismissal without notice is a reasonable sanction.
This case is a warning to employers to make sure they don't simply assume that dismissal without notice is the fair sanction in a gross misconduct situation. In almost all cases, dismissal without notice will be a fair sanction, but it is important that employers consider mitigation first.