Huddleston led media operations at BT for the past eight years with responsibility for all of its brands including BT Vision, BT Broadband and BT Business.
A BT spokesman said: "Steve Huddleston is no longer an employee of BT and we do not comment on individual circumstances."
His future at the company became unclear in February after BT moved its £75 million media planning and buying account out of Publicis’ Vivaki and into Maxus.
At the time it emerged that he was on leave from the company for personal reasons.
BT subsequently informed its agencies that Jenny Bullis, its head of consumer media, was overseeing Huddleston's responsibilities.
BT moved its media into Maxus following lengthy negotiations with WPP's Group M and it came less than two years into a three-year contract that Publicis signed with BT.
Huddleston oversaw the media review for BT in 2008 which resulted in the appointment of Starcom and Zed Media to the consolidated business.
At the time, Starcom retained media buying duties, while adding media planning, which was previously handled by Mediaedge:cia, which also pitched for the business. Zed Media, part of the ZenithOptimedia Group, retained online buying.
Prior to joining BT, Huddleston was a media buyer at CDP.