The UK’s Booktrust is marking 20 years since the release of Harry Potter and the Prisoner of Azkaban with an auction of new Patronus images by over 20 illustrators.

Each of the illustrators is designing an original postcard-sized illustration of Patronus creatures.

Bloomsbury Harry Potter book artists such as Kay, Riddell, Jonny Duddle, Levi Pinfold and Emily Gravett will take part, along with designers from MinaLima, the design studio behind the graphic props used in Harry Potter and Fantastic Beasts films.

Prospective purchasers will be able to bid for the pieces online at BookTrust’s eBay for Charity page which will go live at 6pm on 8th July and the postcards will be displayed during that week at Waterstones Piccadilly.

Diana Gerald, BookTrust c.e.o. said: “We are thrilled to be  part of Harry Potter and the Prisoner of Azkaban’s20th anniversary and we know that these exclusive, one-of-a-kind illustrations will be in high demand. It’s lovely to think that a novel which has inspired children around the globe, along with some of the world’s most talented illustrators will help BookTrust to support families and get books into the hands of children across the UK.”