Although some coffee shops offer discounts for customers who bring their own cup, uptake of these offers remains low, at only 1 to 2% of purchases. Yet the impact of the plastic bag charge – which reduced bag usage by more than 83% in the first year – showed consumers were more responsive to a charge than a discount.

“We’re hoping that this charge will remind customers to rethink their use of single-use plastic-lined cups, as it has with plastic bags,” said Simon Redfern, vice-president of communications at Starbucks Europe. “We’ve offered a reusable cup discount for 20 years, with only 1.8% of customers currently taking up this offer, so we’re really interested in working with Hubbub to see how this charge could help to change behaviour and help to reduce waste.”

The trial comes after financial incentives to encourage consumers to use reusable coffee cups have had disappointing results. In 1998 Starbucks was the first coffee chain in the UK to offer users of reusable cups a discount – 10p – before upping it to 25p in 2008. In 2016 it doubled this to 50p, but take-up remained low and it is now back to 25p.