Thames Water has reminded people not to pour Christmas dinner fat down the sink to prevent sewers clogging up.
The company has said 25% more fat - about 500 tonnes - goes down drains in December than at any other time.
Fat should be put in a container and, once cold, put in the bin.
To highlight the problem a group of sewer men have posted on You Tube their song 'Bin it - Don't Block It' to the tune of the Christmas carol Good King Wenceslas.
The new lyrics include the line: "Only what comes out of you, should go into our pipes."
Rob Smith, chief Thames Water sewerman and lead chorister, said: "Sewer abuse is a big problem - one well worth making a song and dance about in our view.
"And it's not every day you get to see a rough-and-ready performance of a Christmas carol by a bunch of guys knee deep in poo."
He added: "Cooking fat, sanitary items and other nasties that are wrongly put down loos and sinks end up blocking sewers, and in some cases cause sewage to back up into people's homes, which is truly horrific."
For each hit the carol gets, Thames Water has said it will donate 1p to Water Aid to support the charity's work to improve access to safe water and sanitation to some of the world's poorest people.
The company said beef or lamb fat can be mixed with seeds or food scraps to make nutritious bird feed and meat fat also goes well in gravy.