According to British Glass, the cost of PRNs, which companies buying and using glass packaging are required to purchase, rose from £15 a tonne at the beginning of 2012 to £65 or even £70 a tonne by the final quarter. Some companies faced 10-fold increases in PRN prices, said head of container affairs Rebecca Cocking.
"This has meant added expense for the supply chain, up to and including the brand owner," she admitted. "We hope it's not something that's making people consider plastics packaging instead."
In fact, as she pointed out, recycling targets for glass may already be high, but they are remaining static. "People are saying that glass is a real problem. But plastics have ever-increasing targets, and there are concerns that they don't yet have the necessary reprocessing capacity. We have this temporary 'blip', but there may be bigger problems with plastics."
At compliance scheme provider Valpak, policy director Adrian Hawkes said: "We think the PRN price will come down. The current level isn't justified, since overall targets aren't changing. The only question is how quickly prices will come down. It may be a few months, but it's difficult to predict."
According to Valpak, the price per tonne has historically tended to fall into the £15 to £25 range.
"Last year was very unusual for glass, with a number of factors coinciding," said Hawkes. Two cases of fraud in the aggregate glass recovery sector left a shortfall in recycling rates. This was plugged using mixed coloured glass with its higher sorting costs.
He added: "Overall, the costs of the UK system remain very competitive compared with other systems elsewhere."