Businesses could face action for letting the alley behind their shops become filthy and rat-infested.
Shoppers say the alley running behind shops including Greggs, Finnigan's fish and chips and The Sutton Arms in Sutton High Street is so filthy rats have been seen scampering around.
The council says it is up to the landowners to make sure the alley is kept tindy but, if they fail to do this, they could be subject to legal action.
A 70-year-old shopper from Bushey Road who asked not to be named took pictures of the alley after he was shocked to see rats running around. He said: "I went to get some fish and chips and parked around there and noticed it was absolutely filthy. I could see rats.
"There were black bags everywhere just strewn around and all this mess that had obviously come out of the bags. I think that's what the rats are eating."
Councillor Jill Whitehead, chairwoman of Sutton Council's environment and neighbourhoods committee, said: "The appearance of the town centre is very important and we are working closely with Sutton Business Improvement District (BID) to identify private areas which are in need of cleaning up.
"While the council cannot clear up private properties we have regulatory powers to try and persuade owners to clear up their properties and will take enforcement action if needed to maintain the overall look of our borough."