During the Cultural Revolution faith communities were driven relentlessly underground. Then, in 1978, Deng Xiaoping's liberalization programme began to open doors for the return of religion to Chinese public life. Some properties were restored and religious rights were reaffirmed in the revised Constitution.

But even this limited sort of freedom came at a price: the price of accommodating to the directives of the various party organisations in charge of religion. In the case of the Catholic Church, the so-called Catholic Patriotic Association (PA) had been established in the 1950s in order to guarantee the compatibility of the Catholic Church with Communist party ideals. Those who refused to compromise by joining the PA had to remain underground.

This underground church is today less persecuted, although there are still many bishops and priests in prison, with the latest arrests taking place last December. It seems to be the case that the PA is largely behind the persecutions, informing on underground communities and sometimes insisting on arrests. The PA has no theological raison d'être. It consists of thousands of officials who nominate bishops, decide who teaches in seminaries, evaluate vocations and administer funds -- the proceeds of church assets seized in the 1950s which enable them to maintain their bureaucracy.

Since Deng Xiao-Ping's liberalization China has been steadily improving. But it seems to have reached a plateau and over the last couple of years there is no evidence of continued improvement of its human rights record, specifically in the area of religious freedom. Indeed, I am afraid that over the last year, in the run-up to the Olympics, we've seen the biggest purge of foreign missionaries since the Communist take-over and more arrests of underground Christians than for some years.

So I hope those who will see the shiny new façade of the China of the Olympics won't forget about what is going on behind the scenes.

In spite of all the difficulties -- or perhaps because of them -- the growth of religions in China is astounding. Last year, for the first time, the government-run Shanghai Academy of Sciences did a study and the results showed that 30 per cent of the Chinese say they are believers of some sort. That includes about a third of the 60 million members of the Communist Party itself.

Today it is no problem for the Chinese to have access to religious information over the internet and to buy Bibles which are printed by sanctioned publishing houses. The problem of religious freedom is a more subtle one: the state allows the five official religions (Buddhism, Taoism, Islam, Catholicism and Protestantism) but it tries to control them. It wants to domesticate Christianity and ensure it's compatible with the government's idea of "society".

The result is an "official" version of each religion, and these official Chinese versions often differ quite a bit from non-Chinese variants. For example: China's official Muslims have female imams and official Buddhist monks undergo training in the state-sponsored Buddhist academy where they have to take tests also in politics, to ensure their ideas don't threaten the party line.

Catholics are confronted with a government that wants to run the Church through the Catholic Patriotic Association, independently of Rome, and those loyal to Rome are forced to practice their faith covertly. For Catholics is not a political but a theological problem. Being loyal to Rome does not just mean accepting bishops appointed by the pope. First of all it means to follow the teachings of the Church and this can be difficult in a country that has a one-child policy, often enforced through abortion.

And yet in my experience not only underground Christians, but most of the Catholics that have never known anything but the official PA, want to be Catholic in the full sense. They thirst for information, for knowledge and they greatly appreciate the new freedoms in those regions where they exist. The situation varies widely, locally. But over-all one can say that the influence of the PA is waning, though in some regions they still control the church, that is, they control who will be bishop and push for ordinations without Rome's approval.

In terms of religious persecution, we must not forget the lay people, priests and bishops who are still in prison for their faith. The party line is that no one is in prison because of their faith, but this is untrue. It's just that the authorities classify unwelcome religious activity as crimes against the social order. And people can be sent to labour camps for up to three years without any trial at all.

But a more typical result of being an underground Christian would be to lose one's job - and that, despite the dire effects on the individual and their family, is not going to appear in any human rights statistics.

Raphaela Schmid is a Senior Fellow of the Becket Institute, the academic branch of the Becket Fund for Religious Liberty. She is the author of the 2007 television documentary God in China.