Many collective agreements state that they are to be "binding in honour only". In Marley v Forward Trust Group Ltd the Court of Appeal holds that this applies between the parties to the agreement, ie the union and employer, and does not affect the legal enforceability of terms of collective agreements which are incorporated into contracts of employment of individuals.
Where the terms of a collective agreement are incorporated into employees' contracts of employment, they may be varied from time to time by agreement between the trade unions and the employers, so that the individual contracts are also varied. But, says the Court of Appeal in Robertson and Jackson v British Gas Corporation, if the collective agreement is terminated by the unilateral withdrawal or its terms varied by unilateral action to which the other side does not agree, the individual contracts remain unaffected.
In Young v Canadian Northern Railway Company Limited [1931] AC 83 JCPC, the Judicial Committee of the Privy Council decided that a collective agreement was not intended to be legally binding between the parties to it. In addition it held that the employee could not claim that those parts of the agreement concerning employee benefits were automatically included in his contract.