Panorama journalists bought various chicken products from popular sources around the country.

These products included chicken nuggets - including some of the best known brands on sale in fast food restaurants and supermarkets across the United Kingdom.

All of these products were sent off to the specialist company Indentigen to test them for traces of beef or pork DNA.

The results are featured below along with a link to the companies' responses:

CHICKEN PRODUCTS
Brand	Cow DNA?	Pork DNA?
Sainsbury's Blue Parrot Cafe chicken nuggets	Yes	Yes
Sainsbury's Blue Parrot Cafe chicken nuggets	No	No
Sainsbury's Blue Parrot Cafe chicken nuggets	Trace	No
Sainsbury's Blue Parrot Cafe chicken nuggets	Yes	No
McDonald's chicken nuggets	No	No
KFC Popcorn chicken	No	No
Asda chicken nuggets	No	No
Tesco breaded chicken nuggets	Yes	No
Somerfield breaded chicken nuggets	No	No
Safeway breaded chicken nuggets	No	No
Iceland breaded chicken fingers	No	No
M&S chicken nuggets	No	No
Dairylea Lunchables tasty chicken	Yes	Yes
Dairylea Lunchables tasty chicken	Yes	Yes

Source: BBC Panorama tests