Harris v Donges (Minister of the Interior)  1 TLR; (1952) 2 SA 428; in the Appellate Division of the South African Supreme Court.
CENTLIVRES CJ:....I now return to the Statute of Westminster. The effect of subsection (1) of section 2 is that the Colonial Laws Validity Act no longer applies to any law made after December 11, 1931 by the Union Parliament. Consequently the Union Parliament can now make a law repugnant to a British Act of Parliament in so far as that Act extends to the Union....
So far as I have now considered the Statute of Westminster it is clear that when it refers to a law made by a Dominion such law means in relation to South Africa a law made by the Union Parliament functioning either bicamerally or unicamerally in accordance with the requirements of the South Africa Act.
Mr. Beyers [counsel for Donges] contended that that portion of subsection (2) of section 2 of the Statute of Westminster, which says in effect that no law made after December 11, 193 1, by the Parliament of the Union shall be void or inoperative on the ground that it is repugnant to the provisions of any existing Act of Parliament of the United Kingdom, had the affect of conferring on the Union Parliament the power to amend any section of the South Africa Act (including the entrenched clauses) in accordance with any procedure it might choose to adopt....
I have difficulties in connexion with Mr. Beyers' contention. That portion of subsection (2) of section 2 of the Statute of Westminster to which I have referred confers, by necessary implication, a power on the Union Parliament which it did not possess prior to the passing of the statute, viz., the power to pass a law which will be a valid law although it is repugnant to an existing or future enactment of the United Kingdom. The object was, in other words, to give the Union Parliament a power which it did not possess prior to the Statute of Westminster. But prior to that statute the Union Parliament had full powers to amend the South Africa Act. It is true that the Union Parliament sitting bicamerally did not have full power to do so in that the entrenched clauses could be amended only by Parliament sitting unicamerally and by a two-thirds majority. But there is nothing in that part of subsection (2) of s.2 of the Statute of Westminster which I am now considering to justify the inference that there was any intention to repeal or modify the provisions of s.152 of the South Africa Act....The words "Parliament of a Dominion" in the Statute of Westminster must, in my opinion, be read, in relation to the Union, in the light of the South Africa Act. It is implicit in that Act that the Parliament of the Union must function bicamerally, save in the cases excepted by ss.35 and 152.....In my opinion one is doing no violence to language when one regards the word "Parliament" as meaning Parliament sitting either bicamerally or unicamerally in accordance with the requirements of the South Africa Act.
Mr. Beyers then contended that no country which, like the Union, emerged from a colony into a Dominion within the framework of the British Constitution can be a sovereign State unless it has a sovereign Parliament functioning bicamerally in the same manner as the British Parliament, and that, if this is not so in the case of the Union, it cannot be a sovereign State unless it breaks completely with its past and abolishes the Monarchy. I cannot agree with this contention. It seems to me to be based on the fallacy that a Dominion Parliament must necessarily be a replica of the British Parliament, despite the fact that all Dominion Parliaments have Constitutions which define the manner in which they must function as legislative bodies. There is nothing in the Statute of Westminster which in any way suggests that a Dominion Parliament should be regarded as if it were in the same position as the British Parliament. Indeed it would be surprising if the British Parliament in enacting the Statute of Westminster, which was agreed to by all Dominions, had gone out of its way to change the Constitution of a Dominion without a request from that Dominion to do so. I have looked in vain at the official reports of the Imperial Conferences which led up to the passing of the statute for any request by the Union to the British Parliament for an alteration of its Constitution. On the contrary the authoritative voice of the Union, as embodied in the joint resolution of the two Houses of Parliament, made it abundantly clear that the Union did not desire any amendment of its Constitution and emphasized that the proposed Statute of Westminster should in no way derogate from the entrenched provisions of the South Africa Act.
A State can be unquestionably sovereign although it has no legislature which is completely sovereign...In the case of the Union, legal sovereignty is or may be divided between Parliament as ordinarily constituted and Parliament as constituted under s.63 and the proviso to s.152. Such a division of legislative powers is no derogation from the sovereignty of the Union, and the mere fact that that division was enacted in a British statute (viz., the South Africa Act) which is still in force in the Union cannot affect the question in issue.
I find it impossible to uphold the implications of Mr. Beyers' contention, viz., that after the passing of the Statute of Westminster the Union found itself with a Constitution which had been radically altered-a Constitution which enabled Parliament to sit either bicamerally or unicamerally, no matter what the subject matter of the legislation might be. The South Africa Act...created the Parliament of the Union. It is that Act and not the Statute of Westminster which prescribes the manner in which the constituent elements of Parliament must function for the purpose of passing legislation. While the Statute of Westminster confers further powers on the Parliament of the Union, it in no way prescribes how that Parliament must function in exercising those powers.
The conclusion at which I have arrived in no way affects the sovereignty of the Union. As a result of s.4 of the Statute of Westminster the British Parliament can no longer pass an Act extending to the Union "unless it is expressly declared in that Act that the Dominion..."has requested and consented to the enactment thereof."....This emphasizes that the only Legislature which is competent to pass laws binding in the Union is the Union Legislature. There is no other Legislature in the world that can pass laws which are enforceable by Courts of law in the Union....Consequently the Union is an autonomous State in no way subordinate to any other country in the world. To say that the Union is not a sovereign State, simply because its Parliament functioning bicamerally has not the power to amend certain sections of the South Africa Act, is to state a manifest absurdity. Those sections can be amended by Parliament sitting unicamerally. The Union is, therefore, through its Legislature, able to pass any laws it pleases....To go further afield, it would be surprising to a constitutional lawyer to be told that that great and powerful country, the United States of America, is not a sovereign independent country simply because its Congress cannot pass any legislation which it pleases....
Each House of Parliament is free to prescribe its own rules with respect to the order and conduct of its business and proceedings and that into the due observance of such rules this Court is not competent to inquire, but that this Court is competent to inquire whether, regard being had to the provisions of s.35, an Act of Parliament has been validly passed. To hold otherwise would mean that Courts of law would be powerless to protect the rights of individuals which were specially protected in the Constitution of this country.