TBWA pitched against WCRC, M&C Saatchi, Delaney Lund Knox Warren and Bartle Bogle Hegarty to retain the business it was first awarded almost two years ago.
The review was handled by the AAR and was called after disappointing initial sales and an ad campaign that failed to excite the public's imagination over the possibilities of video phones.
Early work has been followed up by a better-received new campaign that features classic T-Rex song 'Children of the Revolution' and uses the endline "They said it couldn't be done".
3 UK, which is part of Hong Kong telecoms giant Hutchison Whampoa, had earlier denied a review was taking place.
The review was called before the new campaign was launched. Since then sales are understood to have picked up considerably and are running at around 20,000 a month since 3 introduced new lower tarrifs.
In May, 3 UK shook up its marketing department with the appointment of Orange executive Gareth Jones to head its marketing and sales efforts as chief operating officer.
He was appointed by 3's joint chief executive, Bob Fuller, and replaced Lisa Gernon, 3's strategy and marketing director, who moved into an advisory capacity from June 1.
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