On June 29. Beijing ordained Father Paul Lei Shiyin as the bishop of Leshan , Sichuan province, ignoring warnings from Pope Benedict that the priest was unacceptable for "proven and very grave reasons".

While the Vatican has never announced the reason for Lei's unacceptability, Catholic media have reported that he fathered a child with a woman with whom he had been having an affair. Lei has refused to comment on these reports, saying only that he did not enjoy being the subject of "speculation".

"Nowhere else in the Catholic world would he have become a bishop," said Gerard O'Connell, who writes for the Vatican Insider, a website run by La Stampa, a daily Italian newspaper, but Beijing officials insisted on going ahead.

Angered by the obvious slight, on July 4 the Vatican hit back at Lei's ordination with a rare public announcement of latae sententiae (or "sentence given") - in effect, excommunication - saying that Lei's voluntary participation in the ceremony had violated canonical law.

The incident has contributed to the growing rift between Beijing and the Vatican for control of China's estimated 12 million Catholics, a struggle that is threatening to divide the Catholic Church in China.

"It's a very sensitive time," said a scholar in Hong Kong who monitors the church in China. "In my opinion, there will be a showdown - things are coming to a conclusion.

"I've been in this business for 20 years, and I've never seen it get to this point before," the academic said. "Both sides are playing all the cards they have. One of the two will win everything."

Cardinal Joseph Zen Ze-kiun of Hong Kong, speaking at a news conference in July, put it more harshly: "At this moment, it's war." He also took out a half-page advertisement in Apple Daily, sending a strongly worded "urgent appeal" to President Hu Jintao and Premier Wen Jiabao , calling on the two top leaders to reject "rogue public servants" who are "using violence to assist scum inside the church to force bishops, priests, and followers to do things against their consciences."

The trouble began last November when the Chinese Catholic Patriotic Association (CCPA), the Communist Party's organisation that oversees the Catholic Church in China, ordained Father Guo Jincai as the bishop of Chengde . Guo's ordination was not approved by the Vatican because Chengde is not an official diocese.

In December, the CCPA convened the Eighth National Assembly of Catholic Representatives, forcing bishops and priests loyal to the Vatican to attend the meeting against their will.

"The impression we're given by the recent ordinations is that it's no longer a win-win situation," said O'Connell. "It's as if Beijing just wants to win. `You play by our rules or you don't play.'"

A European Catholic priest based in Hong Kong who monitors the Catholic Church on the mainland argues that the current round of illicit ordinations is not new, but just the Communist Party returning to its normal way of doing things. In 2006, there were three illicit ordinations.

"Lei had been prepared for this for 10 years [by the government]," said the Catholic priest. "Chinese authorities also announced the cancellation of the June 29 ordination of coadjutor bishop-elect Joseph Sun Jigen of Handan , a Catholic stronghold in Hebei province, stationing plain-clothes police along roads leading to the church where the ordination was to take place."

Although both the Vatican and Beijing had approved Sun as a candidate, Beijing argued that it alone had the right to set the date of his ordination. Furthermore, Beijing insisted that Guo, now the illegitimate bishop of Chengde, participate in the ordination.

Government officials were unaware, however, that local Catholics secretly held the ordination days earlier. Outraged, officials arrested Sun and two Catholic priests. Sun was released a few days later, but the government has yet to recognize his ordination.

The seven consecrating bishops, all recognized by Rome, and until then in communion with Rome, may also be punished by the Vatican for taking part in the ceremony.

The Vatican conceded that extenuating circumstances may apply, a reference to the fact that the government forced at least some of the bishops to take part in the ceremonies. A priest who is excommunicated cannot celebrate mass or administer or received the sacraments.

The Holy See's announcement signaled to the clergy and lay Chinese that the Vatican was not prepared to cave in on important religious issues.

Observers say the Holy See is concerned that the ordination of illicit bishops is a trend that will weaken the validity of the Catholic Church in China, and it is time to put its foot down. "There's a line in the sand that can't be crossed, and it's ordinations," said a researcher who focuses on the church in China.

The European priest agreed: "In some cases, too much is too much, especially when faith is in danger."

Requests to interview officials of the CCPA and the State Administration for Religious Affairs were turned down. However, the CCPA said in the state media that the failure to fill the vacant posts was hurting the work of the church in China, and so these positions had to be filled quickly.

"Both sides want to have the upper hand regarding the ordination of bishops," said a Western scholar of the church.

The Vatican announcement of Lei's excommunication has had no effect. Ten days later, the third illicit ordination in eight months took place with the elevation of Father Joseph Huang Bingzhang in Shantou , Guangdong province , where the Vatican had already secretly ordained a bishop in 2006.

AsiaNews, a Vatican-affiliated news agency, reported in July that four bishops had been kidnapped and were forced to take part in Huang's ordination ceremony. The agency said Bishop Paul Liang Jiansen of Jiangmen , ordained in March 2011, was seen sobbing as police dragged him away.

Many priests and lay people refused to take part in the Shantou ceremony, where police stood on guard to prevent any opposition. Bishop Paul Pei Junmin of Liaoning province , was able to boycott the ordination after priests from his diocese staged a prayer sit-in, making it impossible for police to arrest him. Another bishop went into hiding.

The Vatican called the resistance of the bishops "meritorious before God".

Bishops who have co-operated with the illicit ordinations and who took part in the National Conference in December, have come under criticism from their priests, nuns and parishioners. The church researcher said: "Some Catholics are saying, `You're a bishop, and you don't have the guts to stand up? What kind of bishop are you?'"

"I can understand they're being forced to go there, but during the ordinations how could they lay hands?" asked the European priest. "No one could force them to do this. But the psychological pressure is so strong, so they just go along."

Some bishops expressed remorse after taking part in these events, with several going on retreats afterwards. One bishop from Shanghai cried afterwards, saying he was too embarrassed to meet people.

"Under this kind of pressure, you feel like you can't refuse what the government is asking," the European priest said.

"You can see this almost as a baptism of fire," said the researcher. "They're not like the older ones, who went through the Cultural Revolution. Their faith has not been tested before, and they did not pass the test well."

The authorities said they would ordain about a dozen more bishops this year, part of a move to fill 40 vacant dioceses; it's expected that more bishops unacceptable to the Vatican will be on the list, after Beijing accused the Holy See of "foot-dragging" over their approval.

The next illicit ordination is expected to take place in Harbin , Heilongjiang province, with the elevation of Father Joseph Yue Fusheng, who lost an ear several years ago in a fight.

According to O'Connell, Beijing's recent policy is unfortunate as there is a lot of goodwill in the Vatican towards China, with the Holy See happy to work towards a pragmatic solution "without sacrificing fundamental principles".

"The Vatican wants a dialogue, but a serious and honest one. They're not going to be steamrollered, even if they have to wait 100 years. The Vatican has seen empires come and go through the centuries and has faced real difficulties before," he said.

"Think Eastern Europe. There is quite a bit of confidence that sooner or later the church in China will have its freedom."