David Cameron said the discovery of horsemeat in supermarket beefburgers is "extremely disturbing" and "completely unacceptable", during Prime Minister's Questions.
It is a very important issue and it is an extremely serious issue. People in our country would have been very concerned to read this morning that when they thought they were buying beefburgers they were buying something that had horsemeat.
It is extremely disturbing news. I have asked the Food Standards Agency to conduct an urgent investigation into this.
They have made clear there is no risk to public safety because there is no food safety risk but this is a completely unacceptable state of affairs.
They will be meeting retailers and processors this afternoon, they will be working with them to investigate the supply chain, but it is worth making the point that retailers have to be responsible for what they sell and where it has come from.
The horsemeat scandal demonstrates how long and complicated the food chain we all depend on is. Regulating our food supply is expensive.
Some of the best, and worst, jokes and gags from Twitter users discussing the discovery of horse DNA in some supermarket beef burgers.
We've seen the jokes on Twitter but the discovery of horse and pig DNA in beefburgers poses a serious question; where did it come from?