The manager of The Tankard pub in Walworth Road has told the News will leave next year, leading to concerns it could close.
Tom Mitchell, 55, said he is likely to be out by April.
An advert for the sale of the freehold on the pub has also been listed on the website of Fleurets chartered surveyors.
Tom, who has been manager since January 2010, said the business had become “unviable”, and pub company Greene King has agreed to buy him out of his lease.
“The Tankard was good for the first five years, but for the last two or three years the population of our pub has got a lot smaller,” Tom said.
“We’re just a local drinking man’s pub, and I don’t think that business model is viable anymore. The industry has changed, and everyone knows that the way to make money with pubs now is to make them more like restaurants. We just don’t have the space to do that here.
“Last January I actually asked Greene King to give me a discount on the beer [from whom Tom buys his stock] because we weren’t making enough profit.”
The north Londoner, who manages the pub with his daughter, added: “Just to be clear, I was thinking of leaving anyway. I’ve been here seven years, and I think about every six or seven years a pub needs a new face and new ideas, otherwise it gets a bit stale.”
Tom said he doesn’t know what would happen to the building, which has stood since the 1860s, after he leaves. “We know the people with the deepest pockets are building firms,” Tom said, “but I know a lot of local people will be sad if it doesn’t stay as a pub.”
Greene King told the News they did not wish to comment.