Green MSP Mark Ruskell has been accused of taking “cheap shots” at Scottish brewer Innis & Gunn over its refusal to register for the government’s controversial bottle and can recycling scheme.

The brewer’s founder Dougal Sharp says the deposit return scheme (DRS) is illegal and unworkable and that the upfront fees being demanded could force drinks firms out of business.

The business is one of hundreds which risked not being able to trade in Scotland by not signing up for the scheme ahead of Tuesday night’s deadline.

Mr Ruskell, the Mid-Scotland and Fife MSP, attempted to make light of the situation by tweeting “Shame that Innis and Gunn are boycotting Scotland’s bottle #DepositReturnScheme but they’ve always tasted better on draft anyway.”

His comment prompted a flood of complaints. Scottish Conservative MSP Maurice Golden said: “Mark Ruskell might have been trying to be funny with this cheap shot, but there’s nothing amusing about the prospect of important Scottish brands disappearing from the shelves

“Firms such as Innis & Gunn haven’t signed up to DRS because it is unworkable in its current form.

“They can see it poses huge risks to their businesses and thousands of Scottish jobs. Rather than laughing that off, Mark Ruskell should be urging his Green colleague Lorna Slater to pause this fatally flawed scheme.”

Former Scots Tory leader Ruth Davidson said: “An actual MSP here taking cheap shots at a good Scottish business, simply because it’s his party colleague who is cracking on with a flawed scheme, shambolically introduced, which risks materially costing that business.”

One Twitter user said: “The shame is on you for trying to ridicule a Scottish business, trying to survive in the business hostile SNPLand. You should be listening to business voices not dismissing and making fun of them – shameful!!”

Another said: “Are you going to publicly shame all the companies who don’t sign up? And is this really the best or most productive way to engage with businesses?”

Reacting to the comment from Mr Ruskell, a spokesperson for the brewer said: “Innis & Gunn put forward a very clear alternative that utilises existing infrastructure that’s cheaper and easier.

“Dougal’s interviews are in the public domain, his position is extremely clear. Their alternative proposals to DRS are based on real world practical solutions not ideology. This cheap shot doesn’t warrant a response from them on any Twitter channel.”

Only 664 firms among an estimated 4,500 complied with the registration deadline, but the government has been forced to leave the registration process open-ended to encourage more registrations.

Mr Sharp has backed a change in the scheme that will add a few pence onto the cost of every container in a similar way to the plastic bag system. He says this cash could be invested into creating an air tight on street recycling scheme.

Earlier in the parliament Nicola Sturgeon defended the scheme, arguing that opponents were using “opportunism” to attack it

The First Minister said those who had signed up supplied 95% of the recyclable containers.

Circular Economy Minister Lorna Slater admitted yesterday that only 664 businesses had registered with Circularity Scotland. Estimates of the number of suppliers ranges from 2,000 to 4,500.

Ms Sturgeon said: “The relevant statistic is the share of the market – 95%.”