Soft drinks industry bosses have warned a new war on plastic backed by Prince Charles and satellite TV giant Sky could lead to consumers paying £1.40 a week more for their daily milk and add £1.20 to the cost of a six-pack of beer.

The British Soft Drinks association (BSDA) warned those calling for the bottle Deposit Return Schemes (DRS) could lead to huge extra costs being piled on retailers and consumers.

The warning came after Prince Charles gave his backing for DRS in the UK to tackle plastic waste, after broadcaster Sky last night screened a powerful documentary, A Plastic Tide, to launch its Ocean Rescue campaign. It is calling for DRS to help tackle the “dire” problem of marine pollution caused by plastic waste.

Under a DRS system, already being considered by the Scottish government, consumers would pay a deposit when buying drinks cans and bottles which they would get back when they were returned.

“Unlike carrier bag charges, where costs are avoidable, consumers can’t opt out and will have to pay extra on all drinks,” the BSDA said. “A deposit of 20p per container would mean consumers would need to pay an extra £1.40 per week for a daily bottle of milk and £1.20 on a six-pack of beer which they could lose if they don’t return the empty for a refund.

“A DRS could potentially undermine kerbside recycling which is the most convenient system for people to use,” added the BSDA, which said it would also cost retailers £32,000 each for reverse vending machines.

It warned such schemes had not proved successful in other countries.

“In Sweden, fines for littering had to be raised in 2011 in spite of operating a DRS for 30 years,” it said.

“In the US, the state of Delaware repealed its 1979 deposit law in 2010 in favour of a universal recycling programme for households and businesses.”

BSDA director general Gavin Partington added: “Sky should be commended for seeking to raise awareness about the disturbing impact of marine litter and we are happy to support a campaign that wishes to encourage recycling and anti-littering, If we really want to change people’s behaviour industry, campaigners and the Government need to work together to make all forms of littering unacceptable and encourage consumers to always recycle.”

However, the Prince of Wales praised Sweden, Belgium and Germany as leading examples in combating plastic waste, where “deposit schemes exist for plastic bottles using reverse-vending machines, which take your bottle in when you put it into the machine.

“When they introduced this to Germany, the rubbish problem reduced by 95%,” he told Sky News. “It almost seems to me extraordinary that we don’t look more closely at these sorts of initiatives which could make such a dramatic difference.”

Jeremy Darroch, chief executive of Sky, said: “The health of our oceans is in a dire state and we ignore it at our peril, so we are asking all our customers around Europe to help us to bring ocean health to the fore.”