British royals including the Duke of York, the Princess Royal and the Earl and Countess of Wessex attended, as well as princesses Beatrice and Eugenie.
Royals the Earl and Countess of Wessex, Peter and Zara Phillips as well as veteran broadcaster Sir David Frost were among the guests expected to attend.
William and Catherine, who are known as the Earl and Countess of Strathearn in Scotland, were due to travel to Barrow-in-Furness, Cumbria, to learn about the new Astute Class of nuclear powered submarines being built for the Royal Navy by BAE Systems.