This picture shows the birth registration for Prince George of Cambridge, after the birth registration formalities were completed in London on August 2, 2013 .

The plot thickens in the Princess Kate mystery, with suggestions that the designation of Kate as a Princess on Prince Georgie's birth cerificate may have been the result of unilateral action by William, who filled out the registration document for Prince Georgie's birth. 

Richard Palmer, the well-briefed royal reporter for the Daily Express, suggests William may have simply decided that it was time to set the record straight and put it in black and white that Kate is indeed a Princess of the United Kingdom.

Palmer writes, "A senior aide at Buckingham Palace suggested William might simply have taken it upon himself to decide that his wife was a Princess."

This is strong stuff, and it also points out the rather unusual relationship that William appears to have with his press team - ie they always seem to be the last to know. They clearly had very little idea, for example, when the baby was due.

As Palmer points out, the Princess's press office at Kensington Palace has been so consumed with relentlessly promoting the Duchess Catherine narrative that they have frequently told reporters quite categorically that Kate is not and was not a Princess.

Citing just one of those examples Palmer writes:

In May 2011, a Palace spokesman said: “The Duchess of Cambridge would have been Her Royal Highness Princess William if she had not been given her new title, but it is not correct to say she is a Princess now.”

The Palace may simply have wished to promote Kate’s title as a royal duchess and to discourage the world’s media from calling her Princess William or Princess Kate.

 Now, however, the cat is out of the bag and the palace are furiously backpedalling, insisting that Kate was Princess William all along, and that no secret was ever made of that fact.

But reporters who have been in contact with the royal palces every day for the past few years know differently.

The big question of course is why the palace sought to suppress the fact that Kate was a Princess, and push the Duchess title.

It was probably at least in part an attempt to clearly telegraph the fact that Kate and William are most definitely not next in line to the throne, and that we will still have to welcome King Charles and Queen Camilla first, as at the time of the wedding there was a big push for the throne to skip a generation and go direct to William and his Princess.

One question now remains to be answered: Is the description of Kate as a Princess a statement of intent by William reasserting his rights - or just a bad case of baby brain?