Duchess of Cambridge's Orla Kiely dresscoat sparks shopping frenzy

^{The Duchess of Cambridge'sZara dress (left) sold out within minutes. She has also been spotted wearing a similar dress by Erdem.}

Some who rushed to buy lace dress yesterday are already selling it on the auction site for up to £220.

The Duchess' influence on high street purchases has even been dubbed The Kate Effect.

it began when a 25-year-old Kate Middleton was photographed wearing a TopShop tunic dress in 2007 which sold out within 24 hours.

A white £159 Nanette Reiss dress worn by the the bride-to-be caused similar shopping-related hysteria, at one point selling at one a minute.

The store's owner, David Reiss said at the time: ‘We have been inundated with press coverage.'

When The Duchess wore another Reiss dress, the Shola, to meet the Obamas, that dress sold out even more quickly.

^{The Duchess wears a Reiss Shola dress}

As soon as pictures of the Duchess appeared online, the British retailer said they were shifting the £175 pale camel bandage dress at a rate of one a minute. Traffic to its website soared by 500 per cent before it crashed.

Since it sold out, versions of the dress have been selling for as much as $1,000 on eBay. Traffic to the Reiss website has remained boosted by around 200 per cent.

Whistles has also benefited from the Kate Effect with their £95 cream pleated dress - which the Duchess wore in Los Angeles to visit the Inner City Arts Academy in Los Angeles.

Although the dress was three years old an no longer available it sparked a bug surge in sales for the store.