William, Kate and family inadvertently breach Rule of Six on Sandringham walk

The Duke and Duchess of Cambridge and their children have been pictured at a public event with the Earl of Wessex and his family in an apparent breach of the Rule of Six (The Duke and Duchess of Cambridge/Kensington Palace/PA)
The Duke and Duchess of Cambridge and their children have been pictured at a public event with the Earl of Wessex and his family in an apparent breach of the Rule of Six (The Duke and Duchess of Cambridge/Kensington Palace/PA)