Royal wedding: Kate Middleton coat of arms unveiled

Kate Middleton's family has had a coat of arms designed, which will feature on a souvenir royal wedding programme.

Her father Michael commissioned the heraldic design to mark his daughter's marriage to Prince William on 29 April.

It features three acorn sprigs, one for each of the Middletons' children: an idea Miss Middleton suggested.

Royal experts say the coat of arms - which cost £4,400 to make - marks the increased social status of her parents and her potential as a future queen.

Thomas Woodcock, Garter Principal King of Arms, from the College of Arms in the City of London, helped the Middletons with the design.

He said the oak tree was a traditional symbol of England and a feature of west Berkshire, where the family have lived for 30 years.

Mr Woodcock said the gold chevron in the centre of the coat of arms signified Miss Middleton's mother, Carole, whose maiden name was Goldsmith.

White chevronels - narrow chevrons above and below the gold chevron - symbolise peaks and mountains, and the Middleton family's love of the Lake District and skiing.

Mr Woodcock said: "It's not compulsory, but as their daughter is marrying into the Royal Family she will have a need probably to use a coat of arms."

He said Miss Middleton could have been granted her own heraldic design but her father wanted the whole family to be able to use it.

A version of the coat of arms, which can only be used by Kate or her sister Pippa as it denotes a Middleton spinster, will be printed on the back of the souvenir programme. Prince William's will be on the front.

Miss Middleton's heraldic design features a tied ribbon to show she is an unmarried woman.

Overall, it is designed like an elaborate lozenge rather than a shield, a shape reserved for men.

She will be able to use the coat of arms up until her wedding day, after which it will be combined with that of Prince William.

Mr Woodcock said: "With any new design of a coat of arms you have to make sure that the design is distinct not just in colour but in the linear appearance.

"And, as there is a 16th Century coat of arms with a chevron between three sprigs of oak, we've made the differences - dividing the background colours."

Multimedia nuptials

Broadcast footage of the wedding will be streamed live on the royal YouTube channel, accompanied by a live blog put together by staff at Clarence House and St James's Palace.

The commentary will provide historical information and links to previously unpublished photographs and video footage with live updates on social media sites such as facebook and twitter.

This will be the first royal wedding with its own twitter hashtag: #rw2011.

Members of the public have been invited to send their good wishes in the form of a video message to be shown in an online digital wedding book.

150,000 copies of the official souvenir programme booklet will go on sale on the day of the wedding.

The booklet will be handed out along the processional route by a team of military cadets and Explorer Scouts.

The cost will be £2, with proceeds to go to the Foundation of Prince William and Prince Harry.

But it will also be available to download for free the day before the wedding from the official Royal Wedding website.