Reforms to the laws of succession are put forward as a fair way to end discrimination against women and Roman Catholics that would make the country a better place.

But had the changes taken place just over a century ago, some experts believe they would have led to Britain becoming part of Germany's Second Reich and ending up on the other side in the Great War.

Queen Victoria's eldest child was female, but because of the rule of male primogeniture, she was bypassed as heir to the throne and the throne was eventually passed to the Queen's eldest son, who became Edward VII.

The Princess Royal, born in 1840, fell in love as a teenager with Prince Friedrich Wilhelm of Prussia and married him when she was just 17. He died not long after becoming Emperor in 1888.

If female members of the Royal family had been given equal opportunity to succeed to the throne as their male siblings at that time, however, the Princess Royal would have been heir.

She herself died just a few months after her mother in 1901, meaning that had she become Queen the crown would have passed to her eldest child, Wilhelm.

By that date he had become Emperor of Germany and so would have extended his empire to Great Britain and the British Empire.