Why Prince William and Kate Middleton have been banned from signing autographs

There are a number of rules that must be followed if you're a member of the royal family. There's a list of foods they can and cannot eat during royal tours, and royal women are even given guidelines on how to walk down stairs.

Although the younger royals often bend the rules - Prince William and Kate Middleton have often thrown out the royal rule book - there is one thing that they are banned from doing.

When meeting the public, William and Kate aren't allowed to accept gifts from members of the public, and it has also been revealed that the Duke and Duchess of Cambridge are not permitted to sign autographs, either.

Despite the fact that they have many adoring fans who would like to keep a memento of their meeting, for security reasons they are banned from signing anything.

On official outings, Prince Charles usually tells members of the public who ask: 'Sorry, they don't allow me to do that.'

But he broke the rules once during a visit to St Blazey following devastating torrential downpours, when he heard the story of a couple whose home had been affected. As they said their goodbyes, they reportedly asked for an autograph for their son.

Photographer Paul Williams, who was present, revealed that Charles found a piece of paper and signed it for the couple.

He said: 'As everyone knows Royal protocol means that the Queen and Prince Charles never give autographs. They may sign visitors books or official documents, but autographs never.

'Charles astounded his protection squad and asked them to find him some paper, which they did. Then with a detective holding a file for him to rest on, he whipped out his Royal Parker pen and scribbled 'CHARLEY 2010' on it.

'They've gone from the depths of despair losing all of their belongings just before Christmas to having a Royal visit and obtaining an unheard of souvenir.'

It is believed that the rule has been put in place to stop forgery, and is something that the royals have adhered to over the years.