UK supermarket giant Tesco has withdrawn chickens from its shelves that wrongly carry the "freedom food" label.

The label, launched as an RSPCA (Royal Society for the Prevention of Cruelty to Animals) initiative, is meant to guarantee to consumers that the animals they eat were reared according to certain welfare standards. It may only be used under licence from the society, but routine checks exposed the false-labelling breach at a major Tesco supplier.

Moy Park, a leading UK poultry processor based in Northern Ireland, has been using the freedom food labels on Tesco's finest premium own label chickens since July last year, but without permission from the RSPCA. Tesco says it took proof of the accreditation on trust, and the supplier insisted that it used the labels "not by intent but by mistake".

Ann Grain, spokeswoman for the RSPCA, told the Guardian newspaper: "We are outraged that our label can be used by a supplier like this and sold in a reputable store.

"It is extraordinary that Tesco did not check whether its supplier was accredited."

The society is now conducting an inquiry with the grocer and Moy Park and it has asked Moy Park for a guarantee that any printing machinery at its plants is no longer used to make freedom food labels.

Tesco said in a statement: "As soon as the matter was brought to our attention by the RSPCA, we took immediate steps to remove all free range chicken supplied by Moy Park from our shelves and cancelled our free range chicken orders with them.

"We are now reviewing our procedures for checking accreditation with our suppliers."