The starting point here is the ‘restraint of trade’ doctrine. This stipulates that any restrictions on a former employee’s ability to compete with their former employer are unlawful and void, unless certain criteria are met.

For a post-termination restriction to be valid:

• The employer must have a legitimate interest to protect. A restriction aimed solely at preventing competition between the former employee and employer will not be valid. Instead, there must be some form of defined business interest. Examples would include trade secrets and confidential information; trade connections, customers and suppliers; and the skills of the employer's workforce.
• The restriction must be reasonable between the parties. Reasonableness does