HAD it been held in public, the trial of Zhou Yongkang, who was once in charge of China’s vast security apparatus, might have been the most sensational since Madame Mao and her fellow members of the “Gang of Four” were sentenced for “anti-party” activities in 1981. But the authorities were clearly worried about what might be revealed: the trial was held in utter secrecy in the port city of Tianjin, about 120km (75 miles) south-east of Beijing, rather than in the capital itself. No news of it was released until after Mr Zhou received a life sentence for bribery, abuse of power and the leaking of state secrets. Nor was any hint given in the official account of the trial of what many observers believe was the main reason for the case being lodged against Mr Zhou—that he had been a key ally of Bo Xilai, a former member of the Politburo who was himself jailed for life in 2013 for abusing his power. Mr Bo, it is widely thought, was a rival of President Xi Jinping. The sentencing of both men was probably an attempt by Mr Xi to crush political resistance.

By going after Mr Zhou, Mr Xi certainly broke with precedent. Never before had a serving or former member of the Communist Party’s most powerful body, the Politburo Standing Committee, been formally accused of corruption. Ordinary members of the Politburo were fair game: Chen Xitong, a former party-chief of Beijing, was sentenced in 1998 for corruption. Chen Liangyu, who was party chief of Shanghai, was jailed a decade later, also on corruption charges. But for years it had been thought that politicians of Mr Zhou’s rank enjoyed an undeclared immunity. After taking over as China’s leader in 2012 Mr Xi launched a sweeping campaign against corruption, saying it was aimed at “tigers” as well as “flies”. Rumours soon spread that Mr Zhou was the principal tiger that he had in mind.

The bare details of the trial that have been revealed by state media add little to what had been widely leaked about the case. The official news agency, Xinhua, said Mr Zhou was found guilty of accepting a bribe worth 731,100 yuan ($117,750) from Jiang Jiemin, a former oil executive who was later put in charge of overseeing the state’s assets. Mr Zhou was said to have asked Mr Jiang to help arrange business opportunities for friends and relatives. (Mr Jiang was tried in April; his sentencing is awaited.) The court in Tianjin also ruled that Mr Zhou’s son, Zhou Bin, and his wife, Jia Xiaoye, had received bribes (about which they later told Mr Zhou) worth nearly $21m. No details have been given of the secrets Mr Zhou leaked. But the recipient was identified as Cao Yongzheng, an entrepreneur who gained fame in the 1990s because of reports that he had supernatural healing powers.

Mr Zhou is reported to have accepted these charges and to have expressed his regret for the “serious impact” his crimes had had on society, and the “damage” he had caused to “the party’s cause”. It is unlikely that many ordinary Chinese will be especially surprised by these revelations of high-level wrongdoing: cases involving numerous lesser officials in recent months have already made clear how widespread corruption is among the elite. There will be much speculation, however, about whether the sentencing of Mr Zhou will strengthen Mr Xi. It is possible that the jailing of such a big tiger will fuel resentment of him among families of the powerful who—before Mr Xi took over—had benefited from lax supervision of their business dealings. By jailing Mr Zhou, Mr Xi has changed China’s political rules.