Sandwiches in 100% compostable packaging will go on sale at Glastonbury festival which starts on Wednesday, as part of a trial launched by the Co-op.

In what it claims is a first for a national food retailer, the convenience chain says all elements of the packaging – from the base card to the transparent film and the label – are compostable.

Ten types of ready-made sandwich featuring the packaging will go on sale at the chain’s pop-up store at the festival. Compost rubbish bins will be available at the site.

The Co-op will also sell recyclable aluminium cans of spring water and refillable water bottles which can be filled from water taps on the site. The festival has banned the use of single-use plastic bottles this year.

At other big music festivals – Download, Isle of Wight, Latitude, Creamfields, Reading and Leeds – the Co-op has been working with Keep Britain Tidy and bringing back its deposit return scheme for plastic bottles which can be placed in reverse vending machines.