Nicola Sturgeon today defended the heavily-criticised deposit return scheme (DRS), arguing that opponents were using “opportunism” to attack the project.

Facing claims that most businesses had not registered for the scheme ahead of Tuesday’s deadline, 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.

“The relevant statistic is the share of the market – 95%,” Ms Sturgeon told MSPs today.

However, one critic said that if big companies were seen as the biggest culprits then why have small firms been forced to follow suit.

The Scottish Government has extended the deadline to allow more producers to register. It is certain, however, that many will continue to resist until there is more clarity on how it will operate.

Scottish Conservative leader Douglas Ross said: “At midnight on Tuesday, businesses in Scotland were legally required to sign up to the SNP-Greens’ deposit return scheme.

“Thousands of producers rightly decided not to because the scheme is an absolute shambles.

“Lorna Slater, the minister in charge, said just 664 businesses had registered but refused six times in this chamber yesterday to say, how many should have signed up.

“So will the First Minister give us that answer now – how many businesses should have signed up to her government’s deposit return scheme?”

Ms Sturgeon insisted that “when a big change is introduced”, it is” understandable there will be concerns about it”.

She added: “I have deep respect for the concerns that are being raised by businesses. Government will continue to work with business to address those.”

The First Minister hit out at the “sheer opportunism of some opposition parties”, who she said had supported the scheme but “now indulge in knee-jerk opposition”.

Mr Ross noted that none of the three candidates to replace Ms Sturgeon was in favour of the scheme going ahead as planned in August.

He was later forced to apologise to the parliament – “and my mother” – for using what he termed industrial language when a protestor in the public gallery began shouting and had to be removed.

The Scottish Licensed Trade Association continues to express serious concerns over the return scheme.

Colin Wilkinson, SLTA managing director, said: “Yesterday, we were told that drinks producers responsible for more than 95% of containers sold in Scotland have signed up for the DRS along with more than 650 small and medium-sized producers.

“Circularity Scotland says that producers responsible for more than two billion recyclable drinks containers had registered for the scheme.

“However, when you look closely at these figures, just a fraction of firms has registered – 664 out of the 4,000-4,500 that was anticipated. It’s a very low figure and it reaffirms our concerns that this DRS is not fit for purpose.

“We reiterate that we don’t want to scrap the scheme – we want it paused so that our concerns and those of other trade groups representing all aspects of the drinks industry and the supply chain can be carefully considered and addressed ahead of its implementation.

“The DRS as it stands needs to be rethought and adjusted to ensure that smaller businesses are not bogged down by bureaucracy and forced to deal with unnecessary layers of administration.”