The world's biggest advertiser, consumer goods giant Procter & Gamble, has resigned its membership of the Zip TV consortium, citing the involvement of rivals in the interactive television collective.

P&G joined the multi-client consortium in 2003, alongside competitors Unilever and Reckitt Benckiser. The aim was to fund a feasibility study into the launch of an advertiser-funded iTV channel.

Zip TV launched in July 2004 as a "virtual" channel, providing additional content when viewers press the red button on their remote controls while watching an interactive ad through the usual TV channels.

The system allows viewers to return to scheduled programming once they have watched the interactive ad.

Says Zip TV managing partner Andrew Howells: "Zip's business has now evolved. As a result, we now have a more traditional client/agency relationship with a number of consortium members. In this respect, it is understandable that competitive companies within the consortium may seek to work with alternative agencies elsewhere."

Other Zip consortium members include BT, lottery operator Camelot, the government's COI Communications, Honda, Masterfoods, Orange, Woolworths and Gillette. The latter was acquired by P&G last week but will remain a member of the project.

Data sourced from BrandRepublic (UK); additional content by WARC staff