The company that produces Harry Potter and the Cursed Child has released a statement calling the secondary ticket market an ‘industry-wide plague, and one we as producers take very seriously’.

Newly-released tickets for the play based on the popular Harry Potter novel series by J.K. Rowling have fallen victim to touts after going on sale on 21 November. Eager fans reported that tickets were selling out in seconds and reappearing on secondary ticketing websites for thousands of pounds.

Speaking through Twitter, Rowling said: “A reminder: we are committed for fair pricing for Cursed Child tickets. Do NOT buy from touts, as resold tickets are regularly cancelled.”

Staff at The Palace Theatre, where the play is being shown, have so far refused entry to around 60 people trying to see the play with tickets purchased from unauthorised retailers.

Play producers Sonia Friedman and Colin Callender told BBC Watchdog: “The secondary-ticket market is an industry-wide plague, and one which we as producers take very seriously. Our priority is to protect all our customers and are doing all we can to combat this issue.”

A spokesperson from Viagogo, where some users were listing tickets for more than £1,000, told the BBC: “Sellers set the prices on Viagogo and for popular events prices can be higher because there is huge demand and limited supply. However, tickets listed at silly prices rarely sell.

“The reality is that around half the tickets sold on Viagogo are priced at or below face value.”