Will the courts always enforce restrictive covenants?
No. A restrictive covenant is essentially a restraint of trade, and the courts will enforce a restrictive covenant only if it is necessary to protect the legitimate interests of the former employer. The courts will balance the former employee's right to trade and earn a living with the former employer's right to protect its interests, while taking into account that the contract was entered into freely. With this in mind, when drafting a restrictive covenant, an employer must make sure that it is relevant, proportionate and reasonable. For example, if the employer is seeking to stop a former employee from soliciting its clients, a covenant that stops contact with "all" clients will, in most circumstances, be unenforceable. A clause is more likely to be enforceable if it is limited, for example, to clients with whom the former employee has had "material dealings during the last 12 months". This will highlight to the court that the clause is seeking only to protect a legitimate interest. Generally, clauses should be tailored to the individual and should be time specific rather than indefinite.
In Tillman v Egon Zehnder Ltd  UKSC 32 SC, the Supreme Court held that an unenforceable part of a restrictive covenant clause can be severed, making the clause enforceable, provided that the unenforceable provision could be removed without the need to make other changes to the clause (ie the blue pencil test) and without changing the character of the agreement.