Gopal Sri Ram JCA:

[1] There are two appeals before us. They are Civil Appeal No B-02-623-05 ("the first appeal") and B-02-625-05 ("the second appeal"). They vividly illustrate the operation of the doctrine of estoppel in the sphere of procedural law. The relevant facts are as follows. The litigants before us were parties to a joint venture agreement. Disputes having arisen under that agreement, these were referred to arbitration. An award in the plaintiff's favour was handed down on 29 January 1988. Later, on 17 July 1990 the plaintiff (first respondent in the first appeal) filed a summons to enforce the award under the provisions of the Arbitration Act 1952. It was filed in the Appellate and Special Powers Division of the Kuala Lumpur High Court. On 28 February 1992, the appellant in the first appeal and the first respondent in the second appeal commenced an action in the Shah Alam High Court to specifically enforce the joint venture agreement. Then, on 24 September 1993, the appellant in the first appeal and the first respondent in the second appeal took out a summons in chambers in the enforcement proceedings in Kuala Lumpur. By that summons she applied to intervene in the enforcement proceedings and to have them transferred to Shah Alam for the purpose of consolidating them with her own suit. Her summons was made returnable on 30 November 1993. But a day earlier, on 29 November 1993, the plaintiff filed a notice of discontinuance.

[2] I now come to 30 November 1993. The summons for intervention came on for hearing before Abu Mansor J (later FCJ). The order made by his lordship shows that all relevant parties now before us in this appeal were represented: in particular the plaintiff and the appellants in the second appeal (respondents in the first appeal). It reflects that all counsel were heard. It also reflects that an order permitting intervention and a transfer of the proceedings to the High Court at Shah Alam was made. Neither the plaintiff nor the second respondent in the first appeal lodged an appeal against the decision of Abu Mansor J on the ground that the order he made ought not to have been made because the enforcement proceedings had been discontinued a day earlier.

[3] After the transfer of the enforcement proceedings to the Shah Alam High Court, that court, on 4 May 1994 ordered those proceedings to be consolidated with the civil suit before it. Later, on 2 March 1999 consent judgment was entered in the consolidated actions transferring the land that formed the subject matter of the Shah Alam action to the appellant in the first appeal and the first respondent in the second appeal.

[4] In February 2002, after the passage of some nine years after Abu Mansor J had made his order, the second respondent in the first appeal took out summonses to set aside that order as well as the consent order of 2 March 1999. The appellant in the first appeal also took out summonses to set aside those summonses, although I must be forgiven for being unable to comprehend the necessity of these latter applications. For, if the second respondent in the first appeal was unable to persuade the court on its summonses, then cadit quaestio. The latter applications took the matter no further except to incur costs. The learned judge who heard the 4 summonses dismissed them all. His principal ground for the orders he made was this. As the enforcement proceedings had been discontinued, there was no action or suit or proceeding on which Abu Mansor J could have granted intervention and transfer. The enforcement proceedings were dead as a doornail. It followed that there was nothing to set aside. Each side has brought an appeal against the decision made on its respective summonses.

[5] By reason of RHC O. 21 r. 2(1) a plaintiff has an unqualified right to discontinue his or her action against a defendant without leave of the court provided he or she does so before service of the defence. Then, O. 21 r. 3 says this:

(1) Except as prov