They would both have qualified for the titles due to their father being a Prince and them being grandchildren of the monarch through the male line.
Letters patent issued in 1917 assigns a Prince/Princess status and the ‘His/Her Royal Highness’ titles to all children of a monarch’s sons.
This is why Beatrice and Eugenie are Princesses and Zara Tindall is not, because Zara’s royal parent is female (Princess Anne) and Beatrice and Eugenie’s royal parent is male (Prince Andrew).
James and Louise are also children of a Prince, but were granted ‘Lady’ and ‘Viscount’ titles instead.
These are the titles bestowed upon children of Earls, which they are as Prince Edward’s title is the Earl of Wessex.
In 2020, the Countess of Wessex herself stated James and Louise retained their royal titles and styles and will make a choice on whether to use them when they turn 18.
However Lady Louise did not choose this for herself in November of this year and remains Lady Louise Windsor.
Judi James spoke exclusively to Express.co.uk about James, Viscount Severn’s body language from official royal photographs.
She said: “The way that Sophie and Edward have been able to keep both their children away from the spotlight until they felt it was appropriate seems to have resulted in body language signals of both James and Louise that suggest the strongest of family ties as well as a blend of both fun and growing maturity from James in particular.
“Picking litter up from a beach with his parents on one of his first public outings, James looked determined to put in some good work rather than just go through the motions for the cameras.
“He seems to idolise both his mother and his father and his huge hug for Sophie when she was competing in a sporting event suggested a possible touch of hero-worship for the woman who always looks like the most relaxed, comfortable and down-to-earth royal when she is making an appearance or undertaking duties.
“When the family group did pose together on the beach there was a hint of ‘big sister’ affection too as Louise put her hand out in a truncated hug for her younger brother as he stood in front of her.
“While his sense of playful fun was obvious during his earlier years there are also cues to suggest James is growing up into a responsible and caring young man.”
In comparison to their older cousins, very little is known about the Queen’s two youngest grandchildren.
Royals such as Zara Tindall, 40, were raised without any royal titles, however due to being an Olympic equestrian Zara has spent many years in the public eye.
James is currently 15th in line to the throne and his older sister Louise is 16th in line.
The rules were changed when Princess Charlotte was born in 2015 to allow females to stay in the order they were born in the line of succession.
James is believed to be attending Eagle House School, a coeducational preparatory school near Sandhurst in Berkshire.
In April 2015, James and his sister Louise participated in their first overseas engagement by accompanying their parents on a trip to South Africa.
In September 2020, James participated in the Great British Beach Clean with his family at Southsea Beach, in support of the Marine Conservation Society.
James is styled as Viscount Severn. The title acknowledges the Welsh roots of Sophie’s family as the River Severn rises in Wales.