Smartwatches that allow pupils and students to cheat in exams are being openly sold on Amazon. An advert for one such watch, which has 4GB of memory, was offered on the website for £44.95.

“This watch is specifically designed for cheating in exams with a special programmed software. It is perfect for covertly viewing exam notes directly on your wrist, by storing text and pictures. It has an emergency button, so when you press it the watch’s screen display changes from text to a regular clock, and blocks all other buttons,” the seller wrote.

Joe Sidders, the deputy head at Monkton Combe senior school, in Bath, told BBC News that such devices were making exams a “nightmare to administer”. “I expect the hidden market for these sorts of devices is significant, and this offering on Amazon is just the tip of the iceberg,” he said.

Mr Sidders said it was irresponsible to sell such devices and called for exam boards to challenge those involved in making them.

A spokesman for Amazon said the company did not want to comment on the sale of the cheating watches.