The ad, created by Cheetham Bell JWT, carries on the "ultimate embarrassment" strategy and is the fifth in the series. The BACC banned the ad from TV and it will run in cinemas nationwide from this week to early January. Media was planned and bought by Mediavision.
"Vet" shows a vet driving into a farmyard to examine a cow. His old-fashioned mobile phone rings just as the farmer comes to greet him and, desperate to hide it, he shoves the phone up the cow's backside. The camera snaps back to show the farmer looking confused when the phone starts ringing from within the cow.
The cinema spot will be supported by a website, phones4moo.co.uk, launching on 10 December. The site features a game in which players have to find three phones among a herd of cows. They can win Sharp GX10 MMS-enabled handsets and will receive exclusive offers.
The Phones 4U marketing director, Julian Neal, said: "Throughout this campaign we have caught the attention of the target market through funny and cringeworthy scenarios."
Cheetham Bell JWT's chief executive, David Bell, added: "Our core audience of 18- to 34-year-olds are the people most likely to upgrade their phones and respond well to the brief of making the visual work for the brand edgy."
The ad was art directed by Stewart Critch, written by Ian White and directed by Tom Merilion at Joy Films.