It is apparent that some people are still confused as to the status of Camilla Parker Bowles after her marriage to the Prince of Wales. British MP Andrew Mackinlay has 'revealed' that Camilla would automatically become Queen on the accession of the Prince of Wales to the throne. This 'revelation' is not new, and shows the opportunist nature of many politicians, and the danger of politicians and others commenting on technical matters of which they are ignorant or ill-informed.
The wife of a King automatically becomes Queen, not because any Act of Parliament, but because this has been the custom and practice for a thousand years. In the ordinary course of events Camilla would have become Queen Camilla on the accession of Charles to the throne. However the spouse of the Sovereign need not use the title to which she is entitled - and the wives of Kings in Saxon times didn't generally use the royal title, being styled "Lady" instead. It was announced at the outset that Camilla would not use the title of Queen, just as she will not use the title of Princess of Wales.
No change in the law was anticipated, nor is any change needed, either in the United Kingdom or any of the Commonwealth realms, for either usage. The various Royal Titles Acts in the United Kingdom, Australia, New Zealand and elsewhere are not relevant, since they deal only with the title of the Sovereign, and not with that of the Consort or members of the Royal Family. These latter titles are regulated by custom and the royal prerogative, not by parliamentary legislation. The position in Australia and New Zealand is no different to that in the United Kingdom. To formally deny Camilla the title and status of Queen in any realm would require an Act of Parliament in that realm, but this is not necessary - and indeed would be inappropriate - since it is sufficient for the lesser titles to be used in practice.
A distinction must be drawn between the right to the royal style and title on the one hand, and the possession of constitutional powers and authority, which is vested solely in the person of the Sovereign. The Princess of Wales has no constitutional role or authority as their title is derived solely from their marriage to the Prince of Wales - just as with any marriage to a prince or peer. The Queen Consort has no formal constitutional role or authority, and only some insignificant and largely obsolete legal privileges apart from the customary entitlement to the royal style and title. This is equally true in Australia and New Zealand as it is in the United Kingdom.
The suggestion that Clarence House had deliberately mislead the public is incorrect, as they were simply stating what the intention was. Certain commentators may have drawn incorrect inferences from what had been said, but that is immaterial. The official position is simply that Camilla will be styled Princess Consort upon the accession of the Prince of Wales.
Dr Noel Cox