What options does an employer have where an employee who has resigned begins to underperform during the notice period?
As with all instances of poor performance, the employer should investigate the circumstances, rather than assuming that the employee is taking advantage of being in their notice period. The employer should investigate whether or not there is a genuine reason for the performance issues, for example that the employee is sick or is struggling with their workload.
However, if the employer concludes that the employee's poor performance is a misconduct issue, it should consider whether or not the misconduct amounts to gross misconduct that would warrant dismissal without notice. For example, if the employee is persistently disobeying reasonable instructions, this could be grounds for summary dismissal. The employer should follow its own disciplinary procedure and comply with the principles of the Acas code of practice on disciplinary and grievance procedures.
If the employee's conduct falls short of gross misconduct, the employer should assess whether or not it wants or needs the employee to stay until the end of the notice period. If the poor performance is due to the employee's wish to leave, it is arguable that they will not be an effective employee during the notice period regardless of any steps taken by the employer. The employer may consider allowing the employee to end the contract early. The benefits to the employer of this are that it need not pay the employee's salary or benefits after they are released from the contract.
If the employee intends to stay for the notice period, but appears to intend to do as little as possible for the remainder of the contract, the employer should deal with the conduct issues in accordance with its disciplinary procedure and the Acas code. It should make clear to the employee at the beginning of the process that this may result in receipt of a warning, which would be disclosable to future employers as part of the reference process. The potential for a warning on their file may be a strong motivating factor for the employee to improve their performance.