The executive who oversees Everything Everywhere's (EE) range of devices is defecting to HTC, which unveils its new European headquarters in the UK today.
Phil Roberson, one of the most influential people in Britain's mobile industry, is understood to have agreed to move to the Taiwanese smartphone-maker.
Insiders said he had not yet resigned but had told colleagues of the forthcoming move. EE declined to comment, while HTC did not return calls.
Mr Roberson was head of terminals and devices at T-Mobile and was appointed head of devices last year after the merger with Orange to create EE. He looks after the operator's portfolio of devices, and is regarded as one of the most influential gadget handlers in the industry.
Mr Roberson, who was named among the 50 most powerful people in the UK industry by Mobile magazine, negotiated to bring the iPad and the iPhone to T-Mobile.
In January, he oversaw the deal to bring the Motorola Atrix, the smartphone which doubles as a laptop, to Orange as its launch partner.
EE was in the news last week as deputy chief executive Richard Moat was grilled by a House of Commons select committee over issues related to spectrum, the airwaves dubbed the "lifeblood" of smartphones.
As a condition of the merger between Orange and T-Mobile, the combined company was required to give up some of its spectrum holdings.
The sale is expected to bring in over £415m, and MP Tom Watson asked whether the company could justify profiting from selling something gifted to it by the Government in 1991.
Mr Moat replied that the company would have to invest considerably more in next year's spectrum auction, when the operators will be vying for the frequencies necessary for the forthcoming launch of 4G services.
Rivals Vodafone and O2 will go in front of the committee later this week.
HTC will today open its new European headquarters in Slough, which is also the UK base for Research in Motion, the maker of BlackBerry, and mobile operator O2.
The Taiwan-based group has enjoyed massive expansion in the past few years, driven by its range of smartphones running Google's Android operating system.Reuse content