What is the effect of a third party pleading in a personal injury action?

Third party pleadings function as a special type of statement of claim. Indeed, the claim they embody could be brought by separate action. But to avoid a multiplicity of proceedings, the rules permit the claim to be made in the action which has been commenced against the defendant. The object of permitting third party proceedings to be tried with the main action is to provide a single procedure for the resolution of related questions, issues or remedies, in order to avoid multiple actions and inconsistent findings, to provide a mechanism for the third party to defend the plaintiff's claim, and to ensure the third party claim is decided before a defendant is called upon to pay the full amount of any judgment. The avoidance of a multiplicity of proceedings is fundamental to our rules of civil procedure. This has been the case since the reforms effected by the Judicature Acts in the nineteenth century. As Cotton L.J. stated in Searle v. Choat (1884), 25 Ch. D. 727: "the whole tenor of the Judicature Acts is to require all proceedings as far as possible to be taken in one action".