Celebrity chef Jamie Oliver has joined forces with the Royal Society for the Protection of Animals (RSPCA) to pressure retailers and legislators into developing and implementing a labelling system for pork that highlights the conditions in which the pigs are kept.

According to a survey conducted by the RSPCA, only 2% of UK consumers understand the terms used for the labelling of pork products.

According to the RSPCA, pigs reared on the continent and frequently used by food retailers as a source of cheaper pork are not subject to the same welfare standards as UK-reared pork.

Additionally, pork labelled "outdoor reared" is used to refer to pigs who spend up to the first ten weeks of their lives in a free-range system but are then moved to spend the remainder of their lives in factory farms, the RSPCA said.

Through the "Rooting for Pigs" campaign, Oliver and the RSPCA are calling on the EU to set tougher minimum welfare standards for farmers and legislate for clearer labelling to communicate how animals are reared.

The campaign is also looking to push UK supermarkets and other food retailers to voluntarily develop a labelling scheme that addresses pig welfare issues.

"The RSPCA are currently in talks with retailers and this campaign will be going on for a while. Obviously with public support, retailers will be aware of the consumer demand for clearer labelling on pork products," a spokesperson for the RSPCA told just-food.

"We are hoping that in the second phase of this campaign, RSPCA will announce which retailers have taken part and highlight the agreed definitions to use when it comes to labelling pork products."

The campaign comes as Channel 4 prepares to air Oliver's new programme, Jamie Saves Our Bacon, this month.