Years ago, I visited the monastery at Czestochowa in Poland - the home of the famous Black Madonna. Be-camera'd and in full tourist fig, I sauntered unthinkingly through a door and found myself among the faithful at prayer. I have never forgotten the moment. Coming from secular Britain, religious fervour was new to me - and scary. To be fair, if I could believe in something so extraordinary as a loving, omnipotent Deity, I would be fervent too. When faith is, rarely, encountered in Britain, it is polite and tepid. That makes no sense. How can one be lukewarm about God? If He exists, nothing else matters.

During Communist times in Poland the Catholic Church offered the only alternative world view. It  eventually played a vital role in the fall of Communism. Poles credit Pope John Paul II for that (plus President Reagan and Baroness Thatcher) more than their under-appreciated hero, Lech Walesa.

The Catholic Church in Poland never submitted to the Communist State in quite the same way as the Russian Orthodox Church. In Russia the Church had always been subordinate to the secular power of the Tsar. Not that the Tsars weren't devout. Ivan the Terrible spent so much time in daily prayer that there was scarcely the time for all his murder and mayhem. However, there was no doubt who was boss. In the cathedrals, the Tsar's throne was closer to the most sacred part than that of the Patriarch.

The church in Russia was ruthlessly suppressed by Lenin and Stalin. Churches were demolished; priests exiled to Siberia or sent to their God. Sometimes, even under Communism, old people would return to the open practice of religion. The Party's power over them as individuals waned as death approached. In a State where all resources and opportunities were allocated by the Party, no younger person could afford such risk. Yet, every morning as my car waits at traffic lights by a church, I see people crossing themselves as they pass by. Their actions seem natural, casual, even unthinking. Were they furtively doing that during Communism?

Yesterday, at one of the holiest sites of the Russian Orthodox Church I relived my Czestochowa experience. The monastery was business-like enough. Tours were permitted only under paid guidance. The ticket office sold camera permits (a real bargain at £2, with a free CD of church music thrown in). The official guide was devout. She bowed, made the sign of the Cross, kissed reliquaries with a peculiar motion I noticed among the worshippers (wiping the kiss away with a downward stroke of the forehead). However she gave us her talk as worshippers were at their devotions around us. We attracted some irritated glances.

I was embarrassed and my wife even more so. Expecting more of a museum than a functioning monastery, she had brought no headscarf. She was the only uncovered woman. Around us, Russians of all ages were at prayer. We stood awkwardly in the communion line for a while, before leaving abruptly. It just felt wrong to be an unbelieving tourist in the midst of such ardent faith.

Yesterday I realised that - while I cannot myself - I am glad that others can believe in God. I am glad for them because it is a comfort in life's troubles. I am also glad for the rest of us. The believers' faith is a fortress no  State power can ever conquer. If you want a religion to die, ignore it. The most powerful repression, however, will only make it stronger.

There are signs in Britain that our leftist Establishment is girding itself up for an attack on religion. The row over gay adoption gave rise to hostile, even contemptuous, statements from our secular leaders. Attacks from the intellectual Establishment are more and more aggressive. With all respect to our believers, I hope these intemperate attacks continue. They can only strengthen religious belief. A free society needs many groups and individuals prepared to stand up for their beliefs. It does not need a homogenous mass of people who submit to force or fashion.

I do not share their belief, but when I encounter people who stand firm in the face of repression, how can I fail to be impressed? As Britain continues on her path to a police state, we need a wide range of people who are variously motivated to resist. Every Church, synagogue, temple or mosque can be a source of intolerance and reaction. It can also help balance secular power. There is, objectively, no more totalitarian vision than that of the monotheistic religions. Fortunately, their all-powerful leader is not of this world. He need not trouble the rest of us much as he goes about inspiring His people to stand firm against earthly powers.