Greg Christie, a key developer behind Apple’s original iPhone, will step down in a planned retirement later this year, with reports claiming that the move is a result of an internal clash with senior vice president of design Jony Ive.

The co-inventor of Apple’s ‘slide-to-unlock’ feature, who also administered Mac OS X, is departing the company after nearly 20 years of service, after which the human interface team will report to Jonathan Ive instead of iPhone maker’s software head Craig Federighi, according to 9to5Mac.

In a statement to the Financial Times, Apple noted: "Greg has been planning to retire later this year after nearly 20 years at Apple.

"He has made vital contributions to Apple products across the board, and built a world-class Human Interface team which has worked closely with Jony for many years."

The latest departure comes at a decisive time for the Cupertino-based firm, as it is working on finalising elements of its upcoming iOS 8 prior to its public launch at the Worldwide Developers Conference (WWDC) to be held in June in San Francisco, with its launch anticipated in autumn.

Prior to departure, Mr Christie also appeared as an Apple witness in court last week as part of a patent infringement battle with Samsung, to discuss the significance of his ‘slide-to-unlock’ patent, which is one of five being asserted against the South Korean firm in a case seeking over $2bn in damages.

Christie has developed about 100 Apple patents, with more 31 applications awaiting review from the patent office.