A row over the colour orange could hit the courts after mobile phone giant Orange launched action against a new mobile venture from Easyjet's founder.
Neither side will back down in the colour battle
Orange said it was starting proceedings against the Easymobile service for trademark infringement.
Easymobile uses Easygroup's orange branding. Founder Stelios Haji-Ioannou has pledged to contest the action.
The move comes after the two sides failed to come to an agreement after six months of talks.
Orange claims the new low-cost mobile service has infringed its rights regarding the use of the colour orange and could confuse customers - known as "passing off".
Legal battle looms
"Our brand, and the rights associated with it are extremely important to us," Orange said in a statement.
"In the absence of any firm commitment from Easy, we have been left with no choice but to start an action for trademark infringement and passing off."
However, Mr Haji-Ioannou, who plans to launch Easymobile next month, vowed to fight back, saying: "We have nothing to be afraid of in this court case.
"It is our right to use our own corporate colour for which we have become famous during the last 10 years."
The Easyjet founder also said he planned to add a disclaimer to the Easygroup website to ensure customers are aware the Easymobile brand has no connection to Orange.
The new service is the latest venture from Easygroup, which includes a chain of internet cafes, budget car rentals and an intercity bus service.
Easymobile will allow customers to go online to order SIM cards and airtime - which will be rented from T-Mobile - for their existing handsets.