One hundred and ten years after it introduced the world's first moving staircase, the department store Harrods is pioneering another technology: advertisements which talk to your mobile phone.

The Knightsbridge store is understood to be the first British retailer to run print ads featuring 'mobile barcodes', tiny squares showing black and white shapes which, when a mobile phone takes a picture of them, provide information to the phone via the web.

Just as a traditional barcode can identify a product when swiped in a scanner, 'mobile barcodes' allow a phone to interact with a billboard or newspaper advertisement via its camera, and are being embraced by marketers as a way of offering additional information to customers.

The technology does not require a particularly advanced phone - though a 2 megapixel camera with auto-focus is recommended - and once photographed, the Harrods 'code' will direct a reader to one of the store's websites via their phone's web browser.

The codes will feature in a series of ads in London and national media to publicise a new exhibition put on by Harrods called Design Icons, which features Vivienne Westwood, the fashion designer, and the architect of the new St Pancras International station.

In an attempt to shrug off its establishment image and show it is embracing the digital age, the Knightsbridge store will also set up a profile on MySpace, the social networking site, and send out alerts for events at the exhibition using 'Twitter', a messaging service favoured by the Silicon Valley elite.

"We're trying to be a bit pioneering with this," Martin Buckley, head of marketing promotion at Harrods, said. "We want to target a new customer base - thought leaders, as well as students - and this is a way of communicating with them through a different medium that feels new."

Mark Tomblin, director of strategy at TBG, the digital agency which advised Harrods on the campaign, acknowledged that Harrods' traditional customer base may not be overly familiar with the concept of mobile barcodes, but that that didn't bother him.

"This is an attempt to connect with a more tech-savvy audience, and frankly we're quite pleased if the whole campaign remains a bit 'cult'," he said.

Mobile barcodes - sometimes known as QR codes - have been used in Japan and South Korea for several years, and are gradually being embraced by UK advertisers as more and more phones become capable of interacting with objects around them via barcodes.

Film advertisements, for instance, will be able to link to sites with session times, and fashion ads could provide store information such as location and opening times.

At present only the most advanced phones, such as Nokia's 95, have pre-installed software which enables them to read the codes, but several providers offer 'code reading' software which can be downloaded onto other phones, and in the future more phones will have the capability 'out of the box', Nokia said.

Faris Yakob, a strategist at Naked Communications, the London media strategy agency, said: "Anything that helps blend the online and the offline is a good thing, and the mobile - being such as interactive device - is a perfect platform for that."

The reason uptake in European and other developed markets had been slow was because there was disagreement about which standard would be used to print the codes, industry experts said.

One group, which is backed by Nokia, the handset manufacturer, favours a particular type of format known as a 'QR code'. Another wants a rival standard, known as 'dot matrix', to be used.

Daniel Rosen, director of the mobile division at AKQA, which ran a campaign using barcodes for Microsoft's Xbox console last year, said: "Mobile barcodes are definitely going to make outdoor and print media more powerful, but until the mobile carriers begin pre-installing software which can read such codes on their devices, they're likely to stay on the periphery."

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