Most of the plastic food trays that householders carefully wash out after use and put in the recycling bin cannot actually be recycled, it has emerged.
The mixture of plastics used in many yogurt 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 reused. The rest get sent to landfill.
It blames producers for using a mix of polymers, some of them poor quality.
The LGA says the government should consider a ban on low-grade 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.
The LGA says that some simple tweaks could make a massive difference to this situation,
It points to microwave meals which are often supplied in black plastic material.
However, black is the only colour that can’t be easily scanned by recycling machines, meaning that process becomes unnecessarily complicated.
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.
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 re-used.
- 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 are difficult 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.
The LGA wants plastics manufacturers to work with councils to prevent materials that limit recycling entering the system in the first place. It is also calling for government to consider banning low-grade plastics, particularly those for single-use items.
“We need an industry-wide, collaborative approach where together we can reduce the amount of material having an impact on the environment,” said Cllr Judith Blake, who is the LGA environment spokesperson.
“But if industry won’t help us get there, then the government should step in to help councils ensure we can preserve our environment for generations to come.”
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.”
The BBC contacted the British Plastics Federation which represents manufacturers for a comment but has yet to receive a response.
The LGA report comes hot on the heels of a study from the National Audit Office that suggests that half the packaging reported as recycled is actually being sent abroad to be processed.