A Chinese national flag is seen in front of a GlaxoSmithKline office building in Shanghai. (2013 file photo/ Reuters/Aly Song)

This week, GlaxoSmithKline (GSK) confirmed reports in Britain's Sunday Times that a video of its former China head, Mark Reilly, having sex with his Chinese girlfriend in his own apartment had been e-mailed to the firm's chief executive in March 2013. It had apparently been filmed without the knowledge of either Reilly or his girlfriend, and no one is sure who is behind it.

The new detail is just the latest headache for the pharmaceutical giant's China business. It is already facing a huge corruption scandal and is accused of using travel agencies, doctors and consultancies to pay 3 billion yuan ($483 million) in bribes to increase sales and push prices higher. Reilly is stuck in China and was charged with corruption charges last month. He may face decades in prison.

But is the sex tape much of a surprise? Perhaps not − in modern China, allegations of corruption and sexual exploits have become intertwined in the past few years. And if you've been following China recently, you'll know there's a clear precedent for sex tapes and corruption allegations: Lei Zhengfu.

A screenshot from Lei Zhengfu's leaked video A screenshot from Lei Zhengfu's leaked video

Back in 2012, Lei was the Chongqing Beibei District Party Secretary. It was an important position in a big city well-known for corruption and scandals, but he was hardly a name known to international media. That changed on Nov. 20, when an extremely unflattering video clearly showing Lei mid-coitis began to spread on the Chinese Internet. Lei became famous all around the world, and he was soon removed from his position and later sentenced to 13 years in prison on corruption charges.

Lei's sex tape had apparently been secretly filmed in a bid to extort him, with the 18-year-old woman in the video hired to entrap the corrupt official. A man accused of arranging the woman and the video was later sentenced to 10 years in prison. Zhu Ruifeng, the blogger who exposed the video, later said that he had at least five more videos of different Chongqing officials, though these do not appear to have leaked yet.

China, of course, is not the only country that has high-profile scandals featuring secretly filmed sex tapes. In 2009, for example, America's then Ambassador to Russia, John Beryle, had to step in when a secretly filmed video of a U.S. diplomat in a sexual liaison was released online. Modern technology has of course made secretly filming people easier, and social media has made reaching a wide audience with the resulting videos even easier.

In China, however, it does seem remarkable the extent to which corruption scandals have merged with sexual scandals over the past few years. For example, during the fall of Bo Xilai, undoubtedly the most notorious scandal of the past few years, rumors swirled about Bo's alleged liaisons with mistresses. When Bo was finally denounced by the Communist Party, the statement noted that Bo "had or maintained improper sexual relations with multiple women." When a scandal engulfed former railways boss Liu Zhijun, Chinese readers were told by state media that Liu had 18 mistresses, "including actresses, nurses and train stewards." Other mistresses have sometimes revealed themselves on social media when their government official lovers dumped them.

This all happens with such frequency that once a corruption scandal occurs, it's completely reasonable to expect that allegations of sexual impropriety will follow. In another important point, secret recordings of officials are frequent and are often released when the official does something unflattering (last year a Chinese official was dismissed after being secretly filmed insulting his constituents at a lavish lobster dinner, for example). As the GSK sex tape shows, perhaps it isn't just Chinese officials who need to worry.

Unfortunately, we may never know how Reilly's secret sex tape fits in to all this: It remains unclear who made it and why they sent it to GSK's CEO (Reilly is separated from his wife, and there are no indications that the video is anything other than embarrassing). The private investigator hired to help discover who was behind the sex tape and other corruption allegations, Peter Humphrey, was arrested in June 2013. He has been held by Chinese authorities ever since.