On 18 June, Great Yarmouth Magistrates' Court heard that the employee was caught as a result of stepped up security measures following the unrelated theft of three chapters of JK Rowling's Harry Potter and the Order of the Phoenix in a separate incident in 2003.

After pleading guilty to taking the books over an 11-month period in 2007, the employee was ordered to do 180 hours of unpaid work and pay costs of £60.

The books were sold on the internet for around £5 each. It is not clear how many were stolen or how much he had gained from selling them.

The Eastern Daily Press reported that Sara Borthwick, of the prosecution, said: "The operations director reported to the police that she had suspicions that the defendant had been taking books off-site and had been selling them on eBay.

"He was seen in and around areas on the shop floor where his jobs did not ordinarily allow him to go."

Defending counsel, Malcolm Simpson said: "He was only selling books made available to the public through the normal channels. He has lost a promising career at Clays as a result of this offence. He expresses a great deal of remorse for having done it."

Clays employees were previously allowed to take home certain books with permission. The books in question were neither top secret or rare.

The employee has now been sacked by Clays for gross misconduct. St Ives declined to comment on the story.