The simple truth is that no amount of police effort can eradicate certain human needs. The intensity of the public reaction to the crackdown reflected not just the lack of credibility of such government programmes, but also how social values have changed in modern times.

The report aired by CCTV on Sunday claimed the city's thriving underground sex trade was being protected by po lice.

Watch: CCTV news report on sex trade in Dongguan

According to local media reports, Guangdong party secretary, Hu Chunhua, ordered the crackdown straight after he watched the report. On Thursday, Xinhua reported a special task force involving the city's entire police force would conduct a three-month, provincial-wide campaign to eradicate prostitution. Guangdong provincial public security chief Li Chunsheng also vowed to root out police involvement in the trade.

While many countries legalise or at least regulate prostitution, mostly for public health and to prevent crime, mainland authorities see such solutions to the "problem" - to quote a recent editorial - as "blasphemy against civilisation".

The emergence of such a thriving sex industry in a place like Dongguan is a complicated matter and should not simply be treated as a moral issue. It could also be argued that, compared with polluting state-controlled energy corporations, or manufacturers of tainted infant milk formula, or official corruption, the sex trade is more honest.

It is an open secret that Li Dongsheng , the former deputy national police chief who worked for two decades at CCTV, introduced at least two anchor women as wives to senior officials including Zhou Yongkang - a real irony for the state broadcaster who exposed the Dongguan sex trade.

According to sources, some Dongguan police were tipped off before the Lunar New Year about the looming crackdown. The biggest players with the most at stake were warned to dodge police raids. Media reports said many hotels, saunas and massage parlours avoided being raided by claiming they were carrying out renovations or had simply closed for business. It was also reported that more than 60 per cent of the working women had been warned to stay at home until the campaign passed.

On a more pragmatic level, the police move could cost Dongguan dearly, not only to the sex industry directly, but also the livelihoods of taxi drivers, cosmetics and fashion retailers, and landlords. Others say the crackdown could wipe 50 billion yuan (HK$64 billion) from Dongguan's economy, or 10 per cent of the city's gross domestic product.

And while the police might drive the sex industry out of Dongguan, many believe it will simply move elsewhere.

"Many of the businesses have relocated to Ronggui and Nanhai townships in Foshan , and others have gone to Zhongshan ," one knowledgeable person said "They are offering higher commissions to the women. These places are less notorious, offering more stable income."

Why is it okay to turn a blind eye to the rich and powerful who spoil their mistresses with ill-gotten money while barring sex workers from making a living?