Official ties between the Vatican and Beijing - widely expected to be realised next year - will reopen a fierce debate on religious freedom within the mainland's Catholic Church. Bishops of the official church said normalisation of relations would mean a brighter future for Catholics on the mainland, including up to 10 million underground worshippers who frequent churches not registered with the Government. State-approved Bishop Li Du'an of Xian, Shaanxi province, said: 'Underground bishops say we do not recognise the Pope. That is not true, of course. But now if the Pope recognises China and China recognises the Pope, there is no point staying underground any more.' But some underground bishops who have been loyal to the Pope for decades are not so sure. An insider said a small number were disappointed. Some even said the pontiff 'must have lost his mind in agreeing to establish ties with China'. Sceptics who oppose the link fear underground bishops face more persecution. In October, the Vatican news agency reported that a document issued by the Communist Party said a mainland-wide purge of unofficial Catholic churches would soon follow a normalisation in ties. The document reportedly said bishops who refused to co-operate with the Government would be sent to seminaries for 'special education' for at least a year. It appears some of their anxieties are not without foundation. In recent weeks, special meetings have been held in provinces such as Anhui and Zhejiang to promote 'patriotic influence'. Several bishops who refused to co-operate have reportedly been detained. Clergy in Shanxi's Fengxiang county, a stronghold of underground Catholicism, were recently rounded up for special sessions. Sources said funding has also been made available by Beijing to Shanxi authorities to carry out a crackdown against underground Catholicism. A mainland source confirmed that the Communist Party's Central Committee had issued a document calling on cadres to strengthen the 'patriotic force' in the Catholic Church. It was understood that during secret talks held between the Vatican and Beijing, the latter agreed in principle to scrap the China Patriotic Catholic Association - quasi-official body set up by the Government to control the official church. 'When the state leaders promised to scrap the patriotic associations, they thought most churches were patriotic or loyal, but now they understand the situation was not as simple as they had thought,' the source said. 'Now some government officials have to do something to ensure that churches will be patriotic after ties are established with the Vatican.' Observers said mainland leaders were concerned that if the association was abolished or sidelined, a new form of control would need to be put in place to curb unwanted 'foreign influence'. A source who has monitored the Catholic Church in China said the state-approved church would step up training of young priests. Underground bishops with strong local links would probably be 'relocated' to reduce their influence. Although the power of appointing bishops had been a sticking point between the Holy See and the Government, observers said it was no longer considered a stumbling block. 'It should not be too difficult for a consensus, as there are still bishops who are acceptable to both the Vatican and China,' the source said. Ties with China are bound to be controversial. Just last week, Pope John Paul called on mainland Catholics to remain faithful to their beliefs. For years, China has tried to coerce underground bishops and their followers into the state-approved Catholic church by putting pressure on them to register.