The deposit return scheme (DRS) has become the latest political battleground between the Scottish and UK governments.

Essentially a plan to boost recycling, it aims to reduce littering and improve the environment.

However some businesses have voiced concern about the impact it will have on them.

Wrangling over its introduction has led to claim and counter-claim from politicians in Edinburgh and London.

Here, the PA news agency answers some of the key questions about the scheme and the row over it:

– What is the DRS?

Under the scheme, consumers will pay an extra 20p deposit on the container when they purchase a drink in shops.

This deposit would be returned when the container is handed back, either at a shop or a reverse vending machine.

Details of the scheme were first drawn up by the Scottish Government in 2019, including the target materials of glass, PET plastic and cans.

Circular economy minister Lorna Slater, a Green MSP who joined the Scottish Government after the last Holyrood election, is overseeing the introduction of the DRS.

However the scheme administrator is Circularity Scotland – a not-for-profit company funded by the drinks industry rather than a Government agency.

– What do businesses think about DRS?

Some business groups in Scotland were vociferous in their opposition to the initial proposed launch date of August 2023.

The Scotch Whisky Association has raised concerns about the inclusion of glass.

In November 2022, hundreds of business leaders in the drinks and hospitality sectors called on Ms Slater to pause and revise the scheme, saying the August 2023 date was not realistic.

The Scottish Conservatives also called for the scheme to be delayed, and they called on SNP backbenchers to support the move at Holyrood.

However other business groups, including the trade body for soft drinks, backed the DRS.

– Why was it delayed?

The SNP leadership election earlier this year led to Humza Yousaf becoming First Minister, replacing Nicola Sturgeon.

In April, he announced the DRS launch would be delayed to March 2024 as part of a “reset” between Government and business.

But he also blamed the UK Government for creating uncertainty around the scheme by delaying an exemption under the Internal Market Act (IMA).

This post-Brexit law seeks to govern trade around the UK.

– What did UK ministers want to change?

Initially, the UK Government said Scottish ministers had not formally applied for an exemption, something the SNP and Scottish Greens strongly disputed.

In May 2023, UK ministers decided the scheme could go ahead but the glass element of DRS was not granted an exemption under the Internal Market Act.

Including glass would create “permanent divergence” in the market, UK ministers argued, as a planned DRS scheme in England will not encompass glass bottles.

– How did the Scottish Government react?

The Scottish Government said the refusal to allow glass in its DRS undermines devolution, with Westminster accused of intruding on measures agreed by Holyrood.

Ms Slater said it was an attempt to “sabotage” the Scottish DRS, while Mr Yousaf said it will be “extremely difficult” for the scheme to go ahead without glass.

However the head of Circularity Scotland has said it is possible for the DRS to launch without glass.