Penalty on Early Termination of Employment

Q: An employer enters into a one year contract of employment with a senior level employee with a specific and unambiguous clause that says:

TERMINATION OF EMPLOYMENT

Three calendar months notice period will apply if your employment is terminated at any stage. Should the notice period be shorter than 3 calendar months, then the defaulting party must pay the balance of the salary equating to the remainder of the notice period not served (eg: should the employee request to leave with a 1 month notice period, then the employee must pay the employer the salary amount for the balance of the 2 months).