In an interview with The Stage, published yesterday, Mr Wearing said: "I have no choice. It is creatively impossible for me to remain."
He said the "straw that broke the camel's back" was a refusal by the new controller of BBC1, Peter Salmon, to back a screen adaptation of a novel by the crime writer Janet Neel.
That decision, he suspected, had been based upon the feedback from United States-style focus groups, which he believes are having a bigger and bigger say in what the BBC commissions.
Veteran producer Kenith Trodd, who quit the BBC a year ago after branding its drama department "a total mess", said the departure of the head of drama serials would be a big loss.
Mr Trodd, whose own credits include the Dennis Potter plays Pennies From Heaven and The Singing Detective, described Mr Wearing as "the only man of integrity" still holding a high post in the BBC's strife-torn television drama department. "For the executives he is a kind of fig leaf covering what is going on," he said.
Mr Wearing, who has been outspoken throughout his career, and almost left two years ago, was not available for comment yesterday.
The BBC issued a brief statement which read: "Michael Wearing is due to retire next year and is obviously discussing his future plans outside the BBC, so he may decide to go sooner rather than later."
Mr Wearing did indicate in the interview that he has other work - what he called his "parachute" - lined up. Having received a special Bafta award last year for his outstanding contribution to British television, he should not be short of alternative offers.
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