(1) Subject to subsections (2), (3) and (4), an employer shall not -

(a) prohibit an employee from taking up employment with another employer, outside the work schedule established with the first named employer, or

(b) subject an employee to adverse treatment for taking up employment with another employer, outside the work schedule established with the first named employer.

(2) An employer may restrict an employee from taking up employment with another employer, outside the work schedule established with the first named employer, where such restriction (in this section referred to as an 'incompatibility restriction') is proportionate and is based on objective grounds.

(3) Where an employer imposes an incompatibility restriction on an employee -

(a) details of the incompatibility restriction (including details of the objective grounds on which the incompatibility restriction is based) shall be included in the contract of employment, or