Nike has become the first UK company to have a Twitter campaign banned, after the advertising watchdog decided that its use of the personal accounts of footballers Wayne Rooney and Jack Wilshere broke rules for not clearly telling the public their tweets were ads.

Nike, which has lucrative sponsorship deals with the Manchester United and Arsenal footballers, ran the Twitter campaign as part of a wider marketing push under the Make It Count advertising strapline.

A tweet posted by Rooney, who has 4.37m followers, said: "My resolution — to start the year as a champion, and finish it as a champion...#makeitcount gonike.me/makeitcount".

A tweet from Wilshere, who has followers, said: "Jack Wilshere stated "In 2012, I will come back for my club — and be ready for my country.#makeitcount.gonike.me/Makeitcount".

The Advertising Standards Authority, which dealt with its first Twitter investigation in March over a Snickers campaign using Katie Price and Rio Ferdinand, received a complaint that it was not clear the footballers' tweets were advertising.

Nike UK said both players were well-known for being sponsored by the retailer which argued that Twitter "followers" would not be misled about the relationship it had with the players.

The company said it has spoken to both players about their "goals for 2012" and they were free as part of the campaign to independently reply or retweet consumer tweets "at their own discretion".

The company added the web address in the tweet was clearly branded as Nike, and that the message carried the company's ad strapline, making it clear which tweets by the players were personal and which were ads.

The ASA said it was understood from its investigation that the final content of the tweets was "agreed with the help of a member of the Nike marketing team".

The ASA said the average Twitter user would scroll through many tweets a day, quite quickly, and that as such the marketing code states that ads must be "obviously identifiable".

"We considered that the Nike reference was not prominent and could be missed," said the ASA. "We considered there was nothing obvious in the tweets to indicate they were Nike marketing communications."

The watchdog added: "In the absence of such an indication, for example #ad, we considered the tweets were not obviously identifiable as Nike marketing communications and therefore concluded they breached the [advertising] code. The ads must no longer appear. We told Nike to ensure that its advertising was obviously identifiable as such".

In March the ASA conducted its first investigation into a Twitter ad campaign. The campaign by Snickers paid Katie Price and Rio Ferdinand to tweet about the chocolate bar.

The ASA cleared it of complaints that it had broken UK advertising rules.

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