T-Mobile is to invest more than £10m in a new advertising campaign that will include the first interactive ad on Freeview.

The mobile arm of Germany's Deutsche Telecom has recruited Saatchi & Saatchi to develop the campaign, which will include a 30-second interactive spot on digital terrestrial TV.

Produced by interactive agency Weapon 7, the animated Freeview ad features attempts to get viewers to work out how much they spend each month on calls and texts.

Although interactive ads have been a feature on Sky for some years, the relative lack of bandwidth on the Freeview platform has made them costly to produce and so hindered their development.

Steven Hess, managing partner at Weapon 7, said the interactive ad was a "development" of a similar campaign running on Sky but tailored to the demands of the platform.

To make it work, ITV will broadcast the interactive part of the campaign, in this case three pages of additional information, using its Freeview bandwidth.

"Using the Sky model we can get red button interactivity seven days a week, but in Freeview that is limited to people pressing at that moment in time," he said.

Despite the limitations of the platform Mr Hess said the ad was a valid means for T-Mobile to engage with a rapidly expanding audience.

"Freeview is a growing platform and I expect the use of interactive advertising to grow particularly as we get towards analogue switch-off, which will bring more bandwidth into play."

The T-Mobile campaign, which runs under the tag line, "The world's not so rigid anymore", will also run in cinemas, on outdoor sites in London and across the country as well as online, promoting T-Mobile's new tariff plan, Flext.

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