‘It was a very difficult decision because on one hand there was a great team and a top club like Juventus,” explained Axel Witsel last week. “But on the other there was a crucial offer for my family that I couldn’t turn down.”

The Belgium international’s surprising move to Tianjin Quanjian did not attract the same attention as Oscar or Carlos Tevez, although in terms of the Chinese Super League’s burgeoning reputation as the new pacesetters in the global transfer market, it is perhaps even more significant. In exchange for joining the newly promoted side, managed by Fabio Cannavaro and based in one of the world’s most polluted cities, the 27-year-old from Liège will be paid a basic salary of €18m (£15m) for the next five years with bonuses expected to take his overall income close to the €100m mark if he lasts the course.

If those figures are nothing out of the ordinary when compared with the estimated £32m a season Tevez will take home, what makes Witsel’s decision so intriguing is his status as a regular for one of Europe’s leading national teams who turned his back on the chance to join the Italian champions and contenders for the Champions League. Judging by most of the comments on his Instagram account, however, where mercenary is one of the kinder words used to describe to him, most supporters have already made up their minds.

Yet even after Mikel John Obi announced he was ending his 10-year association with Chelsea to move to Quanjian’s local rivals, Tianjin TEDA, the Chinese gravy train looks in danger of hitting the buffers. Last Thursday, two days after an editorial that urged clubs to control their spending appeared in the People’s Daily, the official newspaper of the ruling Communist Party, a spokesman for the General Administration for Sport said it would “regulate and restrain high-priced signings, and make reasonable restrictions on players’ high incomes. We must take building hundred-year clubs as the goal.”

Cameron Wilson, a Scottish journalist who runs the website Wild East Football and has lived in China for 12 years, says: “You can’t understand football in China without looking at the country as a whole. Everything is connected here. What happens in the Chinese economy has a big effect on football and it’s the same with politics. Social movements like people’s change in attitudes and the progressiveness of society – it all affects things in a much bigger way than it would elsewhere. The big teams are bankrolled by huge companies who pour money into the game for political favour. But it’s gone beyond that.

“There’s an ostentatiousness about it now. Teams are trying to outspend each other because they want to be known as the ones who have spent the most money,” adds Wilson. “At some nightclubs in China they will have a scoreboard on the wall telling you which table spent the most on booze. It’s kind of like that in football. There’s a celebration of materialism and extravagance. It’s a little bit like Thatcher’s UK in the 1980s minus the big hair.”

China’s president, Xi Jinping, underlined his wish to turn the world’s most populous nation into a football superpower in 2015 when his central reform leading group published a 50-point plan that included plans for every level of the sport, from professional to grassroots. The government’s latest intervention last week is unlikely to signal a move away from that plan, although it does reflect a growing recognition that Chinese clubs have been paying over the odds for foreign players due to the market’s over-reliance on a small number of powerful agents.

In July 2011, Guangzhou Evergrande – now owned by China’s second-largest real estate group and the Alibaba Group – purchased the Argentinian forward Darío Conca from the Brazilian club Fluminense for a record £7m. The deal made him one of the world’s best-paid players and was brokered by a mysterious agent called Joseph Lee from the Kirin Sports agency.

Born in Hong Kong, Lee moved to China in 1980 to try his luck as a professional player but failed to make the grade. Instead, he set up a conduit for aspiring Chinese players to be trained in Brazil and was in the right place at the right time when the Chinese top flight was relaunched in 1994 as the National Football Jia A League. Between 1998 and 2005, China Daily has estimated Kirin Soccer arranged for more than 200 Brazilian players to move to China.

Lee’s status as the country’s most influential agent – he has even been referred to as China’s Jorge Mendes – persuaded Evergrande’s president, Xu Jiayin, to enlist his help, with the subsequent arrival of Conca and Italy’s 2006 World Cup-winning Marcelo Lippi, who is now coaching China’s national team.

“He was one of the first bridges between Brazilian and Chinese football,” says Pippo Russo, a sociologist from Florence University whose book The Orgy of Power: the Counter Story of Jorge Mendes, the Patron of Global Football was published in October. “Two years ago, he bought the academy of Desportivo Brasil that was built up by the Traffic Sports agency and remains a very influential figure in China.”

Lee’s close relationship with the Brazilian agent Eduardo Uram also helped to smooth the arrivals of the Italy internationals Alessandro Diamanti and Alberto Gilardino in 2014. Uram is an ally of Mendes and Russo and believes it is likely he and Lee have also collaborated on several deals in recent years as the Chinese market has soared in value.

Mendes, who lists José Mourinho and Cristiano Ronaldo among his clients, has become a key player in the emerging Chinese market having sold 30% of his GestiFute agency to Foyo Culture and Entertainment – a subsidiary of China’s biggest investment conglomerate Fosun International – in 2014. Owned by the tycoon Guo Guangchang, in November Fosun purchased almost 17% of Portugal’s largest bank, Millennium BCP, and also has interests in other major Portuguese companies.

Last January, GestiFute and Foyo announced the strengthening of their “strategic partnership” at a ceremony in Shanghai and within weeks the latest round of big-money signings started rolling in to the CSL.

Guangzhou Evergrande’s record €42m move for Jackson Martínez – the Colombian striker who had moved to Atlético Madrid from Porto a few months earlier for €35m – was officially arranged by his agent, Luiz Henrique Pompeo, but Mendes is also understood to have been instrumental in the transfer.

“He is now involved in different roles – not only with his players but also simply brokering affairs,” says Russo. “In general, Mendes is setting up a system of economic power in the far east. We know he was also a key actor in the buying of Valencia by Peter Lim, another Asian businessman who has rooted himself in European football, and we also know that he is working closely with China via Fosun.

“It is a strange situation because there are a lot of agents involved with China,” adds Russo. “We can say that Jorge Mendes is often involved in many of those transfers. But at the moment the most active in China is Kia Joorabchian, mainly because the market is focused on Brazilian players.”

The list of last season’s foreign players – three non-Asians are permitted for each club’s starting lineup, plus another as substitute – shows at least 20 Brazilians on the books of Chinese clubs. Last year, Joorabchian, the Iranian-born businessman who brokered Tevez’s controversial move to West Ham in 2006 and has links to the Israeli super-agent Pini Zahavi, was behind the record-breaking transfers of Ramires (£25m from Chelsea) and Alex Teixeira (£43m from Shakhtar Donetsk) to Jiangsu Suning, whose owners, Suning Holdings, purchased a majority stake in Internazionale last June. He managed to surpass those figures with the deal that took Chelsea’s Oscar to Shanghai SIPG last month, with the Brazil international establishing yet another Asian record fee of more than £50m.

Despite the obvious attraction of a five-fold increase on the salary he was earning at Zenit St Petersburg, Witsel’s decision to move to China remains curious. Having begun his career at Standard Liège, he joined Benfica in 2011 in a deal that was brokered by Luciano D’Onofrio – Standard’s part-owner at the time and Zinedine Zidane’s former agent. Despite being convicted in France in 2007 for his part in a series of football corruption scandals and eventually barred from practising as an agent by Fifa, the man known as Lucky Luciano is understood to have received a 10% share in the player as payment from Benfica, who subsequently sold Witsel to Zenit for his release clause of €40m. Details of the transfer were later revealed by the Football Leaks website, which claimed the transfer also contained clauses to purchase the Argentina winger Nicolás Gaitán for a set fee of €20m.

The move is believed to have been brokered by Mendes, who retains strong ties with the Benfica president, Luís Filipe Vieira, on behalf of D’Onofrio and Witsel’s father, Thierry. Both men were reported by the Belgian newspaper Het Nieuwsblad to have received up to €15m for helping to smooth the transfer to Quanjian.

Of the 16 CSL clubs, Guangzhou Evergrande, Hebei China Fortune, Jiangsu Suning, Shanghai Shenhua, Shanghai SIPG, Shandong Luneng and more recently the Tianjin rivals have spent big money. But with the expected introduction for the new season of a 3+1 rule that will restrict foreign players still further there is a limit to how many high-profile players can be bought, so the race is on to fill the remaining slots before the season starts in March.

“Most players stay for a season or a little bit longer, but the agents who are working with the clubs also have an incentive to want to bring in new players because then they get a bigger cut,” says Wilson. “There’s definitely going to be a lot more movement in this window because some of the players who came last year didn’t really prove successful.

“There’s very few players in the world you can categorically rule out of coming to China now – I wouldn’t be surprised if someone like Wayne Rooney ended up here pretty soon.”