In normal circumstances, notice is usually required to terminate a contract of employment. Notice should be given in a clear manner and once validly given it is effective and does not need to be accepted by the other party. 

If an employee has taken unauthorised absence i.e. gone AWOL, it would be unlikely that this would enable their employer to deem that the employee has resigned. However, unauthorised absence may amount to a repudiatory breach of contract by an employee enabling their employer to bring the contract to an end. Case law has established that a repudiatory breach does not actually terminate an employment contract and a contract will not be terminated until the innocent party elects to accept the breach. In practice, this could mean that the employer writes to the employee confirming acceptance of the unauthorised absence as a repudiatory breach of the employment contract, but this may not be deemed acceptance until the employee has seen the letter.

Employers should also check their disciplinary policies to see what is said about unauthorised absences. Following on from this, employers may wish to commence disciplinary proceedings against the employee. However, it is possible that employers may have difficulty receiving a response from absent employees. In this situation, employers should tread carefully as there are risks involved with holding a disciplinary meeting in an employee's absence unless there is good reason for doing so, for example, the employee persistently seeks to postpone the meeting or fails to attend without any compelling explanation.  

It is important to note that the context of unauthorised absences will differ. Therefore, it is recommended that you obtain specific advice if you find yourself in this scenario.