Hong Kong has turned into a hot spot for books banned in China, with best-selling books digging up dirt on the Chinese Communist Party and eager mainlanders smuggling them home in great numbers.

“I first bought banned books from Hong Kong about seven to eight years ago, during my first visit there,” says a Beijing based businessman and frequent flyer to Hong Kong who preferred not to give his real name. “The airport has a wide selection of such books, dozens of titles to choose from. Now with the upcoming leadership change in China, there are many intriguing stories behind the scene.”

Hong Kong has a huge appetite for information on topics censored in the rest of China and mainland Chinese often fly to Hong Kong to bring back their illegal copies. The businessman, who prefers the pseudonym of Li, already owns a few copies of the latest political best sellers. They include titles such as The Jostling for Positions ahead of the 18th Congress and Princeling Clans and the 18th Congress.

Another book banned by Chinese authorities is The Inside Stories of Wang Lijun versus Bo Xilai, the biggest political story in China. Only a few weeks ago Bo was the Communist Party leader in Chongqing city – when he used to sing this song with the line, “there’s no New China if there’s no Communist Party.. Although the scandal only occurred last month, already books are in print in Hong Kong seeking to explain his ouster and apparent disgrace. News of the scandal, which includes murky corruption allegations, are blocked on Chinese media, including internet forums and microblogs.

“I am more interested in the process and the stories behind it,” says Beijing resident Ivy Ding, who bought a book from Hong Kong that claims to have insights on the affair. “I would like to know more concrete details, not just what the Chinese official media reported. Every time there’s a reshuffle at the top political level, books that spill the beans are in abundance in Hong Kong.”

The 18th National Congress of the Communist Party is a watershed event as it will determine China’s top leaders for the next decade and many of the banned books reveal maneuvers by current leaders to put their trusted allies in their place.

In Hong Kong bookstores, some shops even have special front-row displays called “Banned in China” with numerous books on politics, sexuality and religion. There’s even a store that specialises in books banned on the mainland.

“These books are selling very well, especially this year, titles about the Congress are a hit,” says bookstore attendant Chan, who says most buyers are mainland Chinese.

One of the biggest sellers in recent years was a book titled Prisoner of the State. Published in 2009, it is the memoir of the former Chinese Premier Zhao Zhiyang, who was sacked after the Tiananmen Square protests in 1989. The government banned the book, but 14,000 copies were sold out in Hong Kong on its first day of release.

Chan, who also asked that her real name not be used, says the shops stay connected to their mainland customers via a mobile network service. “Mainland customers can get the latest updates on new arrivals and place their order via SMS and then we ship them to mainland China.”

China’s Constitution supports freedom of speech and the press, but it also says that people must defend ‘the security, honour, and interests of the motherland’. Anyone who publishes material deemed inflammatory or dangerous to state security can be prosecuted.

As a former British Colony, Hong Kong has retained considerable defences of free speech after returning to Chinese rule in 1997. Businessman Li believes this gives Hong Kong a unique ideological battleground for mainland politics.

“Certain information and news items are deliberately leaked there to test reactions. It is like an export that’s meant to be resold for domestic consumption. It’s a way to test the water and influence the political climate in China,” he says.

Stiil, bans make smuggling books to the mainland tricky, says avid reader Ivy Ding.

“If the book cover is removable, I will take it off, or I will put on a different cover to conceal it,” said Ding, explaining how he smuggles books across the border. “Usually, if the quantity is small, it’s no real problem to just stuff them in my hand luggage.”

Li, however, says he was once stopped at the land-crossing between Hong Kong and Shenzhen and ended up arguing with immigration officers about the books in his luggage.

“I said, ‘Why don’t you make public the list of banned books, so that I know what not to buy? Show me the list and regulations, or else how do I know I have violated the rules?’ But the officer remained silent. He wouldn’t or couldn’t show me any list,” he recalls.

Immigration confiscated several books and Li was asked me to remain in Shenzhen the following day and the day after until further notice. While Li has never been fined nor punished for buying the banned books, he says he now avoids buying in bulk.

(Another version of article was first broadcast on Asia Calling, a regional current affairs radio program produced by Indonesia’s independent radio news agency KBR68.)