Prince George is the eldest son of Kate Middleton and Prince William, and third-in-line to the throne behind his father. The five-year-old prince is brother to Princess Charlotte, four, and Prince Louis who has just turned one. The adorable trio were seen playing in their mother Kate’s Chelsea Flower Show garden this week. Related articles REVEALED: How Prince George’s adorable gift was nod to Princess Diana Kate Middleton SHOCK: How William 'made Duchess feel like a SERVANT' George, whose outfits have been copied by adoring royal fans since he was born in 2013, was spotted wearing his signature pair of shorts as he and his sister stuck their bare feet in a babbling stream. Little Prince Louis also wore a cute pair of shorts as he happily toddled along on his own. There is a reason the royal youngsters are always dressed in shorts, as opposed to trousers, even when the weather is not as springlike as it has been this week. Etiquette expert William Hanson told Harpers Bazaar in 2018: "It's a very English thing to dress a young boy in shorts. Prince George is often seen in smart shorts (Image: Getty) The young prince's clothes have been copied by highstreet shoppers (Image: Getty) "Trousers are for older boys and men, whereas shorts on young boys is one of those silent class markers that we have in England. "Although times are (slowly) changing, a pair of trousers on a young boy is considered quite middle class – quite suburban. "And no self-respecting aristo or royal would want to be considered suburban. Even the Duchess of Cambridge." The sartorial expert also spoke about how the custom has historic beginnings. Related articles Royal REVELATION: What George can do that no monarch has for centuries The HEARTBREAKING way Prince William found out he'd be king one day He said: "The usual custom is that a boy graduates to trousers around eight years old. "This is, historically, perhaps due to the practice of 'breeching', which dates back to the sixteenth century. “A newborn boy would be dressed in a gown for their first year or two (these gowns have survived as the modern Christening robe) and then he was 'breeched' and wore articles of clothing that more resembled shorts or trousers than dresses." Both George and Louis, along with Princess Charlotte, wore the world-famous royal christening gown that features cascades of tumbling Honiton lace. Eight-year-old Prince WIlliam wears trousers in 1989, right (Image: Getty) Prince Charles pictured wearing shorts as a young boy (Image: Getty) However, despite the general protocol, George has been seen very occasionally wearing trousers. For the Duke and Duchess of Cambridge’s 2018 Christmas photo, he can be seen striking a cheeky pose as he holds on to his father Prince William. The royal youngster is wearing blue trousers in the snap, which was a more informal moment for the family on their Anmer Hall country estate rather than a public engagement. Prince George was seen wearing long trousers for the first time at Prince Harry and Meghan Markle’s May 2018 royal wedding. On that occasion, the little prince’s outfit was a miniature copy of his uncle Harry’s Blues and Royals Army uniform. Royal commentator Angela Mollard, on podcast “Royals”, spoke about the royal tradition of dressing little boys in shorts. She gave her opinion that Meghan Markle may not choose to follow the same dress code, saying: “I can see [Meghan] putting a little boy in dungarees!”All rights reserved for this news site express.co.uk and under his responsibility