The executive from Apple who was in charge of the troubled iPhone 4's development is leaving the company.

Mark Papermaster has been in charge of Apple's iPhone and iPod hardware department since 2009 when he came over the Apple from IBM.

His leaving is thought to be due to the problems with the antennae on the iPhone 4.

Apple had no comment on his reasons for leaving or whether he resigned or was asked to leave.

In late June, when the iPhone 4 was released, owners began complaining of dropped calls. Evidence them came to light showing that signal strength dropped when the phone was held in a particular way.

The metal casing used to house the antenna was what engineers found to be the problem. Bridging the small gap between the two antennas on the lower left-hand side of the case caused the signal to fade.

The Consumer Reports organization executed an investigation and confirmed the problem and ended up not recommending the phone.

Apple initially downplayed the problem, but the continuing controversy led it to offer free cases to all iPhone 4 owners as they stop the gap from being bridged. Mr Papermaster was not at the press conference where the offer to iPhone 4 owners was unveiled.

A spokesman for Apple said that Mr Papermaster's responsibilities would be taken over by Bob Mansfield who currently oversees engineering for the company's Macintosh products.

He had a role in guiding the development of some aspects of the iPhone and iPod Touch.

Mr Papermaster worked at IBM for 25 years before joining Apple. Although he came on in 2008. he did no start working for Apple until 2009 because IBM sued him for breaching terms of his contract.