WESTMINSTER could block the Scottish Government's under-fire Deposit Return Scheme, according to reports.

Ministers in London are set to refuse permission for a trading exemption for cans and bottles from outside Scotland under the Internal Market Bill.

In normal times, the veto of the flagship policy by the UK Government would spark outrage from the SNP-Green administration, but with criticism mounting over the DRS, and all three SNP leadership hopefuls backing a pause, the opposition may be more muted. 

READ MORE: Minister touts last-minute change to 'farcical' deposit return scheme

Under the DRS - currently due to go live on August 16 - shoppers will pay a 20p deposit when they buy a drink that comes in a single-use container.

They get their money back when they hand the empty container over at a return point.

The cost of that deposit will initially be met by the producer, who will have to add 20p onto every product before it is sold.

However, under the post-Brexit Internal Market Act, goods that have been produced in, or imported into, one part of the UK and comply with relevant requirements there, can then be sold in any other part of the UK without adhering to different regulatory requirements.

That means the DRS will require an opt-out, otherwise, producers from the rest of the UK would be able to sell their wares without having to add 20p on to the cost, putting Scottish firms at a disadvantage.

READ MORE: Speculation UK Government could block SNP-Green Deposit Return Scheme

According to the Scottish Sun, no formal request for an Internal Markets Act exemption has been made by the Scottish Government. 

Their source said: “It’s crystal clear the present scheme is in deep trouble.

“And that’s before the UK Government is asked to relax laws protecting cross-border trade.”

A Scottish Government spokesman said: “We expect a decision from the UK Government as soon as possible. This is what is needed to give industry absolute clarity.”

Responding to the reports, Scottish Green MSP Mark Ruskell said: “To veto this scheme three years after it was approved by Parliament and after businesses have invested hundreds of millions of pounds would not just be bad for the environment, it would destroy jobs and be devastating for those who have invested and got ready.

"It would be a big slap in the face to the many businesses all across Scotland who have already started preparing for the Scheme, some of whom have already spent large amounts of time and money on ordering equipment and starting recruitment. 

"It would also seriously undermine our parliament, our devolution and our democracy. 

“The climate crisis is the most urgent crisis that we will ever face. A lot of young people are sick of being let down. We cannot simply stand by and let it happen again.”

Yesterday, Lorna Slater, the minister in charge of the scheme, told the BBC she was "actively considering" a grace period.

The comments came less than 48 hours before the deadline for producers to sign up to the scheme. 

Meanwhile, all of the SNP MSPs vying to replace Nicola Sturgeon have signalled a willingness to delay the DRS. 

READ MORE: SNP leadership rivals battle over deal with Greens

In an interview with the Scottish Mail on Sunday Kate Forbes said any scheme had to "work for all of Scotland".

"We need to identify why businesses are up in arms, how to adapt the scheme... and then deliver a scheme that actually is going to achieve its aims," she said.

Humza Yousaf told Sunday with Laura Kuenssberg that he would exclude small businesses for the first year of operation if elected first minister.

Speaking more broadly about the SNP's coalition with the Scottish Greens, Ash Regan told The Sunday Show: "We can't have the tail wagging the dog."