The handset maker said that the lawsuit against Orange centres on a patent relating to miniaturisation in the SPV's circuit-board design. The lawsuit was filed in the High Court of Justice in London.
Orange said that it would fight the allegations. "Orange strongly denies any impropriety regarding the intellectual property rights of the SPV and has contacted the parties involved in the design and build of the handset," a spokesman said.
Sendo previously sued Microsoft, which created the SPV's operating system, for allegedly stealing trade secrets from Sendo that were later used in the creation of other Microsoft-powered smartphones, such as the SPV. Sendo developed a handset called the Z100 that was originally to have been the first Windows-Powered smartphone.
The Birmingham, England-based handset maker said its legal action would seek to stop SPV sales. "We have tried to solve the matter in an amicable way. However, we are now in a position that we have to take legal steps," said Sendo chief executive Hugh Brogan in a statement. "We are seeking damages and an injunction to restrain sales of the product."
He also suggested that other companies selling the SPV -- manufactured by Taiwan's High Tech Computer (HTC) and sold by wireless operators under various names around the world -- could face similar legal actions.
"If Sendo believes that its global intellectual property rights are infringed, wherever in the world this might be, we will take steps to defend those rights," Brogan stated.
Sendo sued Orange rather than HTC because its circuit-board patent only covers the UK, but the company has applied for the same patent in other territories worldwide, a Sendo spokeswoman told ZDNet UK. Sendo applied for the circuit-board patent in September 2001, and it was approved on 7 May of this year.
Sendo is now developing a smartphone based on the Symbian OS, which is used by manufacturers such as Nokia and Sony Ericsson.