Orange has begun a court action against soon-to-be-launched mobile service easyMobile.com, over use of the colour orange in its branding.
EasyMobile has dismissed the action, however, claiming that Orange is just "afraid" of the competition.
"After six months of negotiations with EasyMobile, we have been unable to secure a commitment from them not to infringe our rights regarding the use of the colour orange," said Orange.
"Our brand and the rights associated with it are extremely important to us. In the absence of any firm commitment from easyMobile, we have been left with no choice but to start an action for trademark infringement and 'passing off'."
But Frank Rasmussen, UK chief executive at easyMobile, has hit back, saying: "We are extremely surprised by this court claim because we have never used the colour orange in a way that would confuse our customers, and nor do we intend to.
"I believe this is very simple. Orange is afraid of what is going to happen when we launch in the British market."
EasyMobile is a partnership between Telmore UK Ltd and the easyGroup. The service is modelled on the Danish mobile service launched in 2001 by Telmore which uses the internet as its only sales and distribution channel.
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