First-year law student Alexandra Dobney is a fan of the reusable cup scheme launched this September on campus

The proportion of hot drinks sold at the University of Sussex to staff, students and visitors using their own mugs has doubled thanks to a well-publicised pricing strategy promoting sustainable behaviour and deterring the use of paper cups.

A quarter of hot drinks sold since the start of term in September 2018 have been to students, staff and other customers using their own mugs – up from 12 per cent in the previous academic year of 2017-18 and a significant increase from October 2017, when just two per cent of hot drinks were in reusable mugs.

Rather than following the big coffee chains and offering a discount for using a reusable mug, the University instead has set the reusable-mug price as the default price on the menu, with a paper cup a chargeable extra. Since September, the standard prices of hot drinks in university outlets have been for customers using their own mugs and have been reduced to encourage the more sustainable option. Customers needing their drink in disposable cups are charged a 30p surcharge.

This subtle difference in presenting this as a charge rather than a discount can have massive impacts on consumer behaviour, as seen with the success of plastic-bag charges in shops and supermarkets.

Dr Ruxandra Luca, a Lecturer in Marketing at the University of Sussex, said: “While many consumers publicly acknowledge using recycling cups is a desirable behaviour, there is a discord between these explicit attitudes and other underlying processes.

“Our implicit attitudes, those which we are not aware of, might tell us that this is too burdensome. We have good intentions but we don’t always translate our thoughts into action.

“This scheme is successful because it taps into the nudging literature, reflecting the idea that consumers are not always rational and need behavioural nudges to change their behaviour."

“In this case, offering financial incentives, and making it a visible initiative through social proof, where customers see that others are doing this as well, has helped reduce waste.”

Tim Westlake, the University’s Chief Operating Officer, said: “This is a fantastic illustration of us living by our values and leading by example as a University community. We have ambitious targets for our carbon reductions but this proves that relatively simple interventions can have quite profound results.”

And the scheme has proved very popular among students.

Alexandra Dobney, 18 and a first-year law student at the University of Sussex, said: “I started to use it at first mainly because the University of Sussex mugs look so nice but it’s also great that you can save money each time.

“People have their hearts in the right place on environmental issues but sometimes they might need a little help to act. If you wanted a medium to get people thinking about being more sustainable, then coffee at a university is a pretty good way to go - especially when you’ve got a lecture at 9am or 10am in the morning.”

SussexFood, who run the cafes on campus in a partnership between the University and Chartwells, gave away 4,000 reusable cups to encourage take-up of the new scheme.

David Chick, Catering Services Manager at SussexFood, said: “We want to thank students, staff and visitors to the University for getting on board with this initiative and seriously reducing the amount of non-recyclable waste we produce.”

To further reduce the amount of waste going to landfill, the University and SussexFood signed up to the UK’s only paper-cup recycling scheme. Simply Cups sends discarded cups to specialist fibre-recovery facilities in the UK, where the plastic film is removed and recycled, and the paper gets turned into reprocessed fibre. This is then used for packaging or turned into functional new products such as decking or outdoor furniture.