The defendant in this action, the Durban University of Technology, was created by the merger with effect from 1 April 2002 of two technikons, Technikon Natal and the ML Sultan Technikon. (The former of these two institutions was generally called the “Natal Technikon” and is referred to in the papers by the letters “NT”, which I will use to denote it. I will use the letters “MLS” when I refer to the second technikon.) When created by the merger the defendant was named the “Durban Institute of Technology”. Its name subsequently changed to the present one.
 The merger occurred at the instance of the Minister of Education, who was given powers in terms of s 23 of the Higher Education Act 101 of 1997, to effect such mergers by notice in the Gazette. The notice provided for the two merging institutions to be taken over as “going concerns”, and for all their assets to be vested in the new entity. Existing agreements of employment between NT and MLS and their respective employees would be deemed to be agreements entered into between those employees and the defendant and would continue to subsist. Employees would be deemed to have served continuously under the same employer without interruption.
 The plaintiffs in this action are two trade Unions, TENUSA and NEHAWU, who represent employees of the defendant. They litigate in defence of what they contend to be the rights of certain employees and retired employees of the defendant who were employees of MLS prior to the merger. The employment benefits of the employees of the two merging institutions were not identical at the time of merger. Certain of the employees of NT were entitled to a post-retirement medical aid subsidy in terms of their contracts of employment, whereas none of the employees of MLS were entitled to such a subsidy. Prior to the merger the post-retirement benefit had been restricted by NT to persons who commenced employment with NT prior to 1 January 2000. (Other qualifications governing the right to the benefit are not material to this case at present.) It is the plaintiffs’ contention that it has come about that employees of the defendant who were former MLS employees, and who had been in the employ of MLS prior to 1 January 2000, are entitled to the same post-retirement medical aid benefits as their similarly situated colleagues in the former employ of NT, a proposition which the defendant rejects. The plaintiffs seek an order declaring that those former employees of MLS are indeed entitled to such post-retirement medical aid benefits.