Any known act of misconduct, immediate action must be taken against the employee upon knowledge of the misconduct even if the misconduct had happened months (or even years) before it surfaced. Failure to take disciplinary action (or any other action) against the employee shall be deemed as an act of condonation the Company choose not to punish or pursue the alleged misconduct. It is ALWAYS the burden of the Company to prove that the employee has indeed carry out the misconduct and NOT the employee to prove that he/she is guilty of the charge(s).
As the learned Chairman stated in Stamford Executive Center v. Puan Dharsini Ganesan (1986) “The employer must prove the employee guilty and it is not the employee who must prove himself not guilty”.
The quoted case of James v. Waltham  IRLR 202 in dealing with non-performer, it was held as follows:
“If an employee is not measuring up to the job, it may be because he is not exercising himself sufficiently or it may be because he really lacks the capacity to do so. An employer should be very slow to dismiss upon the ground that the employee is incapable of performing the work which he is employed to do, (1) first telling the employee of the respects in which he is failing to do his job adequately, (2) warning him of the possibility or likelihood of dismissal on this ground, and (3) giving him an opportunity of improving his performance. But those employed in senior management may by the nature of their jobs be fully aware of what is required of them and fully capable of judging for themselves whether they are achieving that requirement. In such circumstances, the need for warning and an opportunity for improvement is much less apparent. Again, cases can arise in which the inadequacy of performance is so extreme that there must be an irredeemable incapability. In such circumstances, exceptional though they no doubt are, a warning and opportunity for improvement are of no benefit to the employee and may constitute an unfair burden on the business.”
In another case of Ireka Construction Berhad v. Chantiravathan Subramaniam James  2 ILR 11. In the said case, the learned Chairman has stated:
“It would appear ... that a written warning by the company is essential before it can dismiss the claimant on the ground of poor performance. In the instant case it is not disputed that the claimant was never given a written warning but the company alleges he was given oral warnings which were adequate. That being so, the burden lies on the company to adduce convincing and compelling evidence to prove this.”