Chief Medical Officer Professor Dame Sally Davies has previously said that 'bute' poses only a very low risk to humans. She said:
Horse meat containing phenylbutazone presents a very low risk to human health.
'Phenylbutazone, known as bute, is a commonly used medicine in horses. It is also prescribed to some patients who are suffering from a severe form of arthritis.
The levels of bute that have previously been found in horse carcasses mean that a person would have to eat 500 - 600 one hundred per cent horsemeat burgers a day to get close to consuming a human's daily dose.
And it passes through the system fairly quickly, so it is unlikely to build up in our bodies.
More top news
A baby boy was found abandoned in a church's nativity manger with his umbilical cord still attached.
At least 30 people, mainly patients, were killed when US forces began firing at the facility "mistakenly" thinking it was a Taliban base.
From pensioners to first-time buyers to public sector workers, a rundown of how today's Autumn Statement and Spending Review affect you.