Security arrangements have been stepped up at the Bungay printers of the final instalment in the Harry Potter series.Harry Potter and the Deathly Hallows will be published at one minute past midnight on July 21, and is already the most ordered book in history.

Security arrangements have been stepped up at the Bungay printers of the final instalment in the Harry Potter series.

Harry Potter and the Deathly Hallows will be published at one minute past midnight on July 21, and is already the most ordered book in history.

Clay's in Bungay is printing millions of copies of the 700-page book. As speculation about how the series will end mounts, extra barbed wire has been installed around the works and security guards put on the doors.

Staff have also had to face restrictions - most are not allowed to take mobile phones into work in case they use a camera phone to take pictures. They can only take a small bag into work, which has to be searched. They also need identification to get into the building, and have signed a contract banning them from talking about the book. And workers who normally scan-read the books for errors as they are being printed have been banned from doing so in case the secrets leak out.

In the run-up to the publication of Harry Potter and the Half-Blood Prince in 2005, word about the plot was thought to have spread when a rash of bets on the ending were made in Bungay. And in May 2003, Donald Parfitt, a forklift truck driver at Clay's, pleaded guilty to stealing pages from Harry Potter and the Order of the Phoenix and trying to sell them to the Sun.

A Clay's spokesman said the company would not comment on the Harry Potter book.