Sad Elphick told stop drinking or quit Eastenders.
Officially soap bosses claim his drinking binges are not affecting filming but senior BBC sources are very concerned.
A source said: "It's very difficult to combine heavy drinking with a demanding acting schedule.
"We're told he's arriving on time and doing the business as far as his acting is concerned but at the same time we know he's drinking a lot.
"Basically we don't want the adverse publicity so if he doesn't sort himself out he'll be out on his ear."
The 55-year-old actor, who plays Peggy Mitchell's new boyfriend Harry Slater, has been seen drinking heavily at the bar of the EastEnders' studio.
He drinks vodka followed by Guinness chasers during breaks in filming and during after-work sessions. He has also been spotted drinking at a bar near his home in North West London where he lives with his daughter Kate, 25 - and was back there again yesterday.
During one session he downed 18 shots of vodka and four halves of Guinness.
The actor was left devastated by the death from cancer of his long-term girlfriend Julia Alexander, 52, in 1996.
He admitted turning to cocaine and alcohol and at the height of his problems he was downing two litres of spirits a day.
WARNED: Elphick going to the pub yesterday