West Yorkshire Police confirmed officers were sent to the Peter Boddy slaughterhouse in Todmorden but said the operation was led by the Food Standards Agency.
A force spokesman said: "Officers from West Yorkshire Police attended the premises in Todmorden in a support role at the request of the Food Standards Agency inspectors."
Three men were arrested tonight by officers investigating the horse meat scandal. One of the men was arrested at a plant in West Yorkshire.
Peter Boddy slaughterhouse in Todmorden has been raided by the Food Standards Agency and the police investigating the horsemeat scandal
Police and the Food Standards Agency have raided a slaughterhouse in Todmorden as part of the probe into horse meat in processed burgers.