Why Princess Charlotte, 10, is tipped to 'save' the monarchy and finally end the royal family's 'heir and spare curse'

Princess Charlotte may be just ten years old, but royal experts believe she could have an extraordinary influence on the monarchy's future.

The only daughter of Prince William and Princess Catherine, both 43, Charlotte is said to hold the key to breaking what historians have dubbed the "heir and spare curse" that has long haunted royal siblings.

For centuries, an outdated law placed male heirs above their sisters in the line of succession.

That rule was scrapped in 2013, meaning Charlotte, who sits between Prince George, 12, and Prince Louis, seven, is the first royal girl in British history to benefit from the change.

"For the first time in British history, the spare is a princess, even though she has a younger brother," said Dr Nige Fletcher, a political and contemporary historian, i