A poll by the RSPCA found that only 2% of those questioned understood the terms used on pork products such as 'outdoor bred' or 'free range', suggesting that meant shoppers are confused about the conditions in which pigs are actually reared.
There are currently no set definitions for pork product labelling, so the RSPCA is today launching its 'Rooting for Pigs' campaign, calling on supermarkets and other UK food retailers to work with it to develop and sign up to a voluntary labelling agreement. The charity is also pledging further action later in the year on animal welfare issues, it said.
"We think it is essential that all pig meat be clearly and consistently labelled to allow consumers to make an informed choice," said Dr Julia Wrathall, head of RSPCA farm animal science.
"This survey shows animal welfare is important to more than eight out of 10 people when they're out shopping, even in these hard economic times, and shoppers often seek out specifically-labelled products purely because they want to support certain farming practices"
Dr Wrathall added: "It may come as a surprise, but there are actually no industry-wide agreed definitions when it comes to labelling, in complete contrast to eggs and chickens that do have legal definitions at EU level for terms such as 'free range'. We need clearer labelling - and under a system which makes sense to everyone."
The RSPCA is now calling on retailers to work with it and BPEX on applying agreed definitions for the terminology used on pork product labels.
The charity is also asking the public to show their support by signing a pig petition on its website: www.giveanimalsavoice.org.uk and to buy the highest welfare pork they can afford.
Celebrity chef Jamie Oliver has also been working with the RSPCA, and will lead the debate on pig welfare in his new programme 'Jamie Saves our Bacon' - due to be aired as part of Channel 4's 'Great British Food Fortnight' on 29th January.
Jamie said: "I very much support the RSPCA's 'Rooting For Pigs' campaign as I think that the public needs clearer labelling when it comes to meat, particularly pork and bacon, as the variation in pig welfare across Europe and the world is so diverse."
"How many people outside the industry know the difference between outdoor-bred and outdoor-reared, for example? Not many," he added.
Later in the year, the RSPCA will be calling for a proper review of welfare issues within the EU and UK pig industry and lobbying for a legal requirement within the EU to ensure agreed definitions are complied with when using labelling terms such as free range or outdoor bred/reared on pork products.
"The pig industry has been one of the most proactive of all the UK livestock sectors in seeking ways to progress the health and welfare of the animals it produces, and many UK pigs are reared under good welfare standards throughout their lives," said Dr Wrathall.
"However, even in the UK, where the law and industry practices go beyond EU legal requirements in key welfare areas, some pigs are still kept in ways that fail to meet their needs. This means that, at the moment, of the nine million pigs raised for meat in the UK each year, there is still a significant number that are living out their lives in unacceptable conditions."