Walkers on the Homefield Recreation Ground in Chiswick were shocked to witness workmen saw the heads off snowmen, earlier this week.
When the dog walkers complained, the workers said they were protecting the grass.
Other tales of beheading emerged in Cambridge and Enfield, north London after the weekend’s heavy snowfall led to a surge in snowman-building.
A spokesman for Hounslow Council apologised and said it was the work of two contractors employed to keep the park clean.
“Regretfully – and without valid reason – two workers employed by our contractor decided themselves that this bizarre course of action was necessary. There has not been, nor should there be, any instruction to take any action of this kind,” he said.
The spokesman added: “We have instructed all site staff to use their common sense and let people enjoy the snow in our parks as they are entitled to.”
Suspected instances of snowman and igloo sabotage have also been seen in parks north London and Cambridge, with some residents pointing the finger of blame at local councils.