Soft drinks makers admit more needs to be done to stop people discarding single-use plastic bottles.
Their UK trade body says it will work with government to reduce the number of bottles ending in the sea.
It follows research from Greenpeace suggesting the top six global firms sell plastic bottles weighing more than two million tonnes a year.
The biggest brand Coca-Cola is under fire for refusing to disclose how much plastic it produces.
A study estimated that more than five trillion plastic pieces weighing more than 250,000 tonnes were afloat at sea, and a recent paper showed that even marine organisms 10km deep had ingested plastic fragments.
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Gavin Partington, from the British Soft Drinks Association, said: “We should all be concerned about the problem of marine litter.
“All plastic bottles are 100% recyclable so it is important that consumers are encouraged to dispose of bottles responsibly.
“However, we recognise more needs to be done to increase recycling and reduce littering.”
The Greenpeace study found the six companies surveyed use a combined average of 6.6% recycled plastic in their bottles, and none have commitments to reduce the amount of single-use plastic bottles they use.
Louise Edge, from Greenpeace, said UK drinks makers have until recently been resisting efforts to reduce marine litter through bottle recycling schemes.
She said: “It’s clear that if we’re going to protect our oceans we need to end the age of throwaway plastic. These companies need to take drastic action now.”
After decades of concern, policy on plastic waste in the UK is starting to move. The plastic bags charge has drastically reduced the purchase of throw-away bags, and plastic bottles are now a target.
Scotland has trialled a scheme in which people are rewarded at stores with cash back or discount vouchers when they return plastic bottles. Coca Cola reversed its previous opposition to the trials.
In Germany a 25-cent refundable charge is imposed on plastic bottles.
In some US states a similar charge on aluminium cans prompts children to scour the streets looking for discarded cans to claim the cash back.
The UK government is devising a new litter policy.
The issues aren't straightforward. Minister are keen not to alienate people who already put their used bottles into their own recycling bin. Under a deposit scheme they would be obliged to return bottles to a special recycling point to get their money back.(bbc)