ZONDI AJ Appeal against costs order by the Estate [80] The Estate is appealing against the costs order of the High Court in terms of which that Court ordered it to pay costs jointly and severally with the Minister until 20 January 2017, including the costs of two counsel, after which date the costs were ordered to be paid solely by the Minister. The Estate challenges this order. It contends that the High Court misdirected itself for three reasons. [81] Firstly, the Estate contends that the application primarily concerned the constitutional validity of an Act of Parliament and thus the litigation was primarily between the applicants and the Minister. Secondly, the Estate contends that although Mr Frankel initially opposed the application, this was on a legal, principled basis as the initial relief was incompetent in so far as it did not include common law crimes. This was amended to include such offences and thus, the Estate contends, Mr Frankel was partially successful in his opposition. Lastly, the Estate contends that the High Court erred in disregarding an agreement in terms of which the applicants waived their right to seek costs against the Estate. In doing so, argues the Estate, the Court acted contrary to the pacta sunt servanda principle69 (the principle that agreements are binding and must be enforced) which it contends it was only entitled to deviate from if enforcing the agreement would be unfair or unjust.70 [82] The alternative ground is that the High Court misdirected itself in the exercise of its discretion when applying the Biowatch71 principles pertaining to costs in constitutional litigation. 69 Gbenga-Oluwatoye v Reckitt Benckiser South Africa (Pty) Ltd [2016] ZACC 33; (2016) 37 ILJ 2723 (CC); 2016 (12) BCLR 1515 (CC) at para 22 and Barkhuizen v Napier [2007] ZACC 5; 2007 (5) SA 323 (CC); 2007 (7) BCLR 691 (CC) at para 10 where the Court defined the principle as ―the common law rule that agreements are binding and must be enforced‖. 70 Barkhuizen id at para 69. 71 Biowatch Trust v Registrar, Genetic Resources [2009] ZACC 14; 2009 (6) SA 232 (CC); 2009 (10) BCLR 1014 (CC) (Biowatch). 34