Plastic food pots and trays are often unrecyclable, say councils
Most of the plastic food containers that householders wash out after use and put in the recycling bin cannot actually be recycled, it has emerged.
The mixture of plastics used in many yoghurt pots, ready meal trays and other containers limits the ability of councils to recycle them.
The Local Government Association says that only a third can be recycled. The rest get sent to landfill.
Up to 80% of packaging could be made more recyclable, the industry said.
The British Plastics Federation said companies are working to use more recyclable containers and called for a financial incentive for manufacturers to use more recyclable plastics.
According to the LGA analysis, around 525,000 tonnes of plastic pots, tubs and trays are used by households in the UK every year, but only 169,000 tonnes of this waste is capable of being recycled.
It blames producers for using a mix of polymers, some of them poor quality.
The LGA, which represents councils in England and Wales, says the government should consider a ban on low-grade plastics.
Black plastic 'impossible to recycle'
The LGA says simple tweaks could make a massive difference, highlighting the case of microwave meals which are often supplied in black plastic material.
Black is the only colour that can't be easily scanned by recycling machines, meaning that process becomes unnecessarily complicated.
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Changing the colour of these items would significantly increase the amount that could be used again.
"It's almost criminal to think that some of the plastics being used are difficult to recycle, and black plastic is almost impossible to recycle," Cllr Peter Fleming from the LGA told BBC News.
"The only reason we have black plastic being used by manufacturers is that it makes the food look good."
When it comes to punnets of fruit and vegetables many are made from up to three different types of plastic, including polystyrene, which can't be recycled.
Your views: 'Non-sustainable plastics should be labelled'
Some readers have said they want more transparency from shops about what packaging is recyclable.
Sally Warburton from Guernsey said she wants to buy sustainable items, "but it's a minefield and it sickens me that manufacturers are not being held to account".
Geraldine Fields said consumers "should be told exactly what plastic containers are able to be recycled and what can't".
She added: "I would like to see this information on the packaging so I can choose what products I buy based on their ability to be recycled."
The LGA wants plastics manufacturers to work with councils to prevent materials that limit recycling entering the system in the first place.
And "if industry won't help us get there, then the government should step in to help councils", said Cllr Judith Blake, who is the LGA environment spokesperson.
As well as calling for a ban, the LGA is looking to the government to make plastics manufacturers pay for the costs of collecting and disposing of plastics that can't be recycled.
"Either they can make the change at the front end so their products are easier to recycle," said Cllr Fleming, "or they can start to help pay for the disposal."
Keith Freegard, from the recycling group at the British Plastics Federation - the leading association for the whole of the plastics industry - said designers often use the colour black for packs to indicate they are a more "top of the range product".
He told BBC Breakfast: "Unfortunately those designers didn't realise that when those packs arrived in the recycling factory after it had been separated by consumers, the black dye is not able to be seen by the sorting scanners in the recycling plant - so that does need to change."
He added: "At the moment there's no fiscal or monetary system in the UK that makes designers go for the really good-to-recycle designs and those who make packs which are less easy to recycle, they should be paying more money into the system."
Simon Ellin, the head of the Recycling Association, said manufacturers do have a "big responsibility" and "have got away with it for too many years", but added that "local authorities need to take responsibility as well".
"We have nearly 350 different collection systems up and down the country," he said. "There's widespread confusion, the public don't know how to use it, it's underfunded and it's the proverbial dog's dinner, to be honest."
Five simple solutions to packaging problems
- Margarine and ice cream tubs: Often contain the polymer polypropylene which is very difficult to recycle. An alternative approach would be to make them from the same plastic as water bottles which is easily recycled.
- Microwave and meat packaging: The materials can be recycled but need to be sorted via an optical scanner first. However, as they are predominantly black this makes the process difficult. A simple change of colour could lead to a real increase in recycling.
- Fruit and vegetable punnets: A complicated construction often sees three different polymers used. Simpler designs and more use of recyclable materials could make a big difference.
- Yoghurt pots: Often made from a mixture of polypropylene and polystyrene, which can be hard to recycle. An alternative is to use polyethylene terephthalate, which is also used in plastic bottles and can be easily recycled.
- Baked goods trays: The lining on these trays for cakes and baked goods is often made from difficult to recycle materials. Other options are available which could boost recycling numbers.
Dr Dominic Hogg, the chairman of waste management consultancy firm Eunomia, estimated the cost of dealing with packaging at the household level at around £1bn a year.
"The system we have at the moment, essentially the producers are covering probably something around £10-20 million of that cost," he said - adding that in some European countries, manufacturers would fund the entire amount.
In a statement - which supermarkets Asda and Sainsbury's referred to as their response to the LGA - the British Retail Consortium said retailers were "investing heavily" to find alternatives.
The LGA report comes after a study from the National Audit Office that suggests half the packaging reported as recycled is actually being sent abroad to be processed.