A drug which could cause cancer in humans might have entered the food chain through horse meat slaughtered in UK abattoirs, Labour has claimed.

Shadow Environment Secretary Mary Creagh told the Commons she had evidence that "several" horses slaughtered in the UK last year tested positive for phenylbutazone.

Agriculture minister David Heath told the Commons the Food Standards Agency checks all meat is fit for human consumption.

"Where positive phenylbutazone results are found, the FSA investigates and takes follow-up action to trace the meat," he told MPs.

Ms Creagh called on the Government to reverse a decision to scrap the National Equine Database.