Representation:-

when determining the fairness of a decision to dismiss an employee for misconduct, a tribunal may only attribute to an employer such knowledge of the circumstances of the misconduct as the person responsible for the dismissal possesses at the time of the dismissal (following, of course, a reasonably thorough investigation into the matter); that knowledge does not include any further knowledge or awareness possessed by other senior employees, including the employee's line manager.

For relevant general notes see Unfair dismissal/conduct and misconduct as reason for dismissal and/or Unfair dismissal/fair or unfair? .