Five-year-old George, the eldest child of the Duke and Duchess of Cambridge, has entered Year One at the day school where fees start upwards of £18,474 a year.
Preparatory schools are generally aimed at preparing students for examinations into selective independent senior schools, the majority of which are private.
Previous royals have gone to single-sex prestigious boarding schools as they get older.
Prince Charles famously attended Gordonstoun, which he allegedly referred to it in later life as “Colditz in kilts” – the school has since hit back saying Charles did enjoy it.
His sons Princes William and Harry were not sent to the Scottish boarding school but to Eton in Berkshire as boarders instead.
Will Prince George attend boarding school?
Royal expert Richard Fitzwilliams said the overriding factor in placing George in any school will be one where he “is happy”.
He told Express.co.uk this means it is too early to know if George will attend a boarding school as several key factors are likely to contribute to Kate and William’s final decision.
Mr Fitzwilliams said: “As a child develops certain characteristics come to the fore and they will want to make sure George is happy, that is the really important aspect.
“Alongside that is security and, if it is not going to be a boarding school, there will be the matter of convenience so commuting will have to be feasible.”
As well as choosing a school where privacy would be respected, the most pressing question would be choosing a school which would allow George to “realise his potential in whatever way it transpires”.
Mr Fitzwilliams continued: “As George develops and we see where his interests lie, there will be certain schools that specialise in certain subjects and areas.
“Kate and William will take into account the obvious academic excellence of the school that they think will best suit George depending on where his strengths lie because one of the purposes of anyone’s education is to play to their strengths.”
The Duke and Duchess of Cambridge – who attended Marlborough College – are believed to have selected Thomas’s Battersea for its broad curriculum where ballet, French, art and music all feature an early age to allow children to blossom.
Speculation was heightened last year when a source told The Sunday Times Kate and William may have chosen Thomas’s Battersea as a feeder for the mixed-sex Brighton College.
Rumours are rife George will therefore not follow his father in going to the single-sex Eton College.
Mr Fitzwilliams said the move “would not at all be a surprise, it would be seen as modernising”.
Kate and William are known royal rule breakers, often travelling together as a family, something usually frowned upon in the event of a catastrophe wiping out the family line.
But Mr Fitzwilliams said although it is too early to know if George will board or go to a day school, he is unlikely to rough it at a comprehensive.
The royal expert said: “I would be surprised simply because George will one day be the future King”, although he added wryly “however it is a time of change”.