After reading a headline about her daughter the Princess, Queen Helena says to Prince Cyrus "four minutes earlier and she'd been the next heir."
However, under law for succession to the British throne, all male offspring take precedence over female offspring in the order of succession, so even if he were born after his twin sister, Prince Liam would still be the heir to the throne, not Princess Eleanor.
The British law was changed just prior to the birth of the first Child of the Duke and Duchess of Cambridge allowing the eldest child, whether male or female to be the heir, however, the new law only effected the line of succession going forward and would not impact any prior born royals.
However, under law for succession to the British throne, all male offspring take precedence over female offspring in the order of succession, so even if he were born after his twin sister, Prince Liam would still be the heir to the throne, not Princess Eleanor.
The British law was changed just prior to the birth of the first Child of the Duke and Duchess of Cambridge allowing the eldest child, whether male or female to be the heir, however, the new law only effected the line of succession going forward and would not impact any prior born royals.