McTIERNAN J. The judgment of the Court of Appeal of the Supreme Court of New South Wales from which this appeal is brought upheld a demurrer by the plaintiff to one of the pleas filed by the defendant in an action in which the plaintiff seeks to recover damages for personal injury suffered in a road accident. The plea in question is a plea of issue estoppel. The circumstances giving rise to this situation followed a collision between a motor vehicle being driven by the plaintiff in the present action (the respondent) and a vehicle described as being "owned by the New South Wales Police Department a Department of the Government of New South Wales and then being driven by an officer of the said Department of the said Government". Following this collision two actions were instituted concurrently. In the District Court at Gundagai one Thrift, a constable of police, who was the driver of the police vehicle, sued, as plaintiff, the driver of the other vehicle, Pigram. In this action Thrift, the plaintiff, was successful and recovered a verdict against Pigram. At the same time an action had been commenced in the Supreme Court of New South Wales in which Pigram, as plaintiff, sought to recover damages for personal injury against two defendants, namely, the driver and the owner of the police vehicle. The action against the driver, Thrift, was subsequently discontinued and the action remained as one against the owner of the vehicle being represented in the action by a nominal defendant appointed under the Claims against the Government and Crown Suits Act, 1912 (N.S.W.). Such nominal defendant, who is the appellant in the present proceedings, sought to plead that an issue estoppel arose in his favour from the determination of the issues involved in the action in the District Court at Gundagai. As the parties in the two relevant actions are not the same it is necessary in order to make applicable the doctrine of estopel that the present action involves one of the parties to the earlier action and a privy of the other. The submission on behalf of the appellant was that a person can be privy to a party where there is a community or privity of interest between them (Carl-Zeiss-Stiftung v. Rayner & Keeler, Ltd. (1967) 1 AC 853, at p 935 ). It is claimed by the appellant that where, in an action for personal injury arising out of the use of a motor car, the legal responsibility of the owner is purely vicarious and dependent upon the doctrine of respondeat superior, the owner and driver have such a community of interest as defendants, or potential defendants, to be entitled to have the benefit of an issue estoppel arising in favour of one or the other. According to the appellant's argument, this proposition is restricted to cases where the so-called privies are in the position of defendants. This proposition is, I think, in conflict with the requirement of mutuality which has been accepted as being essential in cases of estoppel similar to the present case. No substantial reason has been advanced for departing from the well-established principle that no one can take advantage of a judgment unless he would also have been concluded by the judgment had it gone against him. No finding in the action in the District Court at Gundagai, if Thrift had lost it, could have operated as an estoppel against the present appellant in a subsequent proceeding. Antecedent to the application of the rule that estoppels ought to be mutual is, however, the establishment of the necessary relationship or privity between the parties. In my opinion, s. 16 of the Motor Vehicles (Third Party Insurance) Act, 1942 (N.S.W.) does not operate to create sufficient community of interest between the owner (as defined in the Act) of a vehicle and the driver for this purpose. Section 16 provides that the driver of certain insured vehicles is deemed to be the agent of the owner, acting within the scope of his authority, for the purpose of enabling a third party injured by the negligence of the driver to recover against the owner who is obliged to procure insurance against liability for bodily injuries or death caused by the use of the vehicle. It is to be observed that s. 16 does not speak in terms of liability, it speaks in terms of agency (cf. Behrendorff v. Soblusky [1957] HCA 84; (1957) 98 CLR 619, at p 622 ). This section does not necessarily create between such parties a relationship of vicarious liability similar to that existing between two joint tortfeasors. It merely attributes the liability of the statutory or imputed agent to the defined owner for purposes of recovery of damages for injury caused by the driving of certain vehicles by the former. The statutory fiction of agency created is for purposes of the Act only. (at p283)