Eileen Barker always wanted to be an actress: "And I didn't just want to be one. I was one. I went straight to the Webber Douglas Drama Academy after school and was in the professional theatre for five years. Mostly in rep. But I got near to the West End. I was at the Lyric, Hammersmith and at Stratford East. And I did some understudying in the West End." It's easy to see why she would have done well on the stage if her embryonic career hadn't been halted by the arrival of a daughter who, from birth, needed careful medical attention. Her soft persuasive voice and steely handsomeness still compel one's complete attention, even here in the pokey confines of the tiny office allocated to her by the London School of Economics where we have arranged to meet.

"So, sociology was really a second choice,"I suggest. "But why sociology? Was there something in particular about the subject which connected to your interest in acting?"

"I think there was. I've only worked this out recently. It's all do with vulgar curiosity, with wanting to have as broad a range of experiences as possible, with exploring beyond what is politically correct. In both sociology and acting you need a range of techniques but you also want to get inside the part you're playing. You want to sublimate yourself in the part, empathise with the character. In sociology that means verstehen. In acting that means Stanislavsky and 'methodï'"

Eileen is talking about the fieldwork that she has been carrying out with new religious movements for the last 25 years, the fieldwork that has led her to spend extended periods of time with such groups as the Unification Church (the 'Moonies'), the International Society for Krishna Consciousness (the Hare Krishna), the Rajneesh movement, and The Family (once known as the Children of God). It is not the type of work that can be done without becoming deeply involved.

'You find you are crying your eyes out. And they are real tears. You are really feeling. And this is where it's like being on stage. Because at that very tearful moment you suddenly notice that the prop man hasn't properly set the dagger with which you're supposed to kill yourself. So you have to become aware. To look around. Sometimes it is very difficult when you are living with a group of people for ages. You feel fear, love, anger, hatred, all the emotions. And then you dash off to the loo to write up your notes. It's the tension between subject and object, between the positivistic and the humanistic. Both have got to be there. So many people go for one or the other. They say you have to be hard and scientific. Sure you do, but if you are just scientific then you will never understand the meaning the religion has for people. Neither can you just go in and have this squishy squashy feeling of having merged with your informants.'

Are there times when she gets so close to people that she begins to lose herself in the part? After all many of the followers she meets during her fieldwork must be relatively young, vulnerable people. Doesn't she ever want to correct their beliefs, suggest they consider other ways of living?

'I do become fond of some people and do develop a friendship. That could be dangerous if I was only studying members of new religions. But I don't only study members. I study ex-members and I study the parents of members, so I have a whole lot of conflicting emotions and friendships.'

Has she ever had worries about becoming converted herself? She has spent lengthy periods of time with people who were excellent proselytizers. What is it that has made her immune to conversion?

'I think it is because I am a real agnostic. A real agnostic. I don't think one can know, so I don't really care what people say is the truth. I am not interested in God; I am interested in people and the way they are affected by religion. There may be a God. But I can't find out if there is one. But I can find out about the extraordinary beliefs that people hold. I never think, 'Oh, you are wrong,' because, for me, there is nothing to test that belief against. I only care about the results of their believing.'

Does she really mean that? Has she never thought anyone was wrong? Aren't some of the ideas she has encountered simply too off the wall to be offered houseroom? 'Well, I suppose I can't help looking a little sceptical if I'm told that the world is going to end next Tuesday.' But surely many other beliefs were nearly as absurd? 'Well, I find everyone believes very, very strange things.' Everyone?' Oh yes. It isn't only people in so-called cults who have peculiar beliefs. Talk to anyone and you'll find they have some weird beliefs. Talk to your photographer.'(She gestures towards NH photographer Guy, who has now arrived and somehow managed to squeeze himself and his equipment into the space left over by Eileen and myself). 'I bet he has some weird beliefs. You only need to go up to the senior common room here and make some slight remark and you'll find people who have nothing to do with church or religion holding some very weird beliefs. The mixtures and the contradictions are really fantastic. You find people who believe in resurrection and in reincarnation and people who insist that there is no life after death but yet believe in Heaven and Hell. The more anthropology and history you do, the more you realise that what we think is natural and normal isn't at all. The normals really are very, very peculiar and when they start to say these new religious people are strange- I'm being serious here - one has to say that the new religions are more systematic and less contradictory, and celebrate paradox far less than your ordinary C of E or Catholic'

I'm finding it difficult to beat away my mental picture of Eileen Barker sitting upstairs in the stuffy male surroundings of the LSE senior common room and gently extracting weird ideas from the bevy of distinguished professors who sit around her. But although there's something pleasantly comic about the notion that such supposedly rational academics entertained ideas that might be weirder than the Moonies or Hare Krishna, I wonder if this sort of normalising of abnormal beliefs could lead to a dangerous acceptance of whatever ideology is embraced by new religious movements (NRMs).

'No. There are some things that are highlighted in new religions of which I disapprove very strongly. People do think of me as a cult apologist, and to some extent I am, in that I do try and show how normal and unthreatening they often are. But there are occasions when they are a threat to their members and to the rest of us in society. And we need to be aware of that. I'm not going to say that Aum Shinrikyo should be allowed to let off sarin gas in the Tokyo underground. And there are the tragic examples of Jonestown, the Solar Temple and Heaven's Gate. But the vast majority of NRMs do not indulge in such horrible behaviour. And many, many deaths have been brought about in the name of old religions.'

It is only when you spend some time in the LSE-based offices of INFORM, the organisation which Eileen Barker founded to provide accurate up-to-date and objective evidence about NRMs, that you realise the truth of her insistence that the 'vast majority'are quite unlike the well-publicised horror cults. INFORM has information on over 3,000 different groups. They are not all strictly new religious movements - the British Humanist Association, for example, is accorded its very own entry - but over one thousand of them qualify for new religious status and most of these have been active in the UK. It isn't just the sheer range of beliefs that is staggering: it is also the different social and cultural locations of each organisation.

This is how Eileen herself summarised this diversity in a recent article: 'Leaders may be rich or poor, and they may be seen as gurus, prophets, teachers, messiahs, gods, goddesses or God. Members may be old or young, black or white, rich or poor. Some live in communes in remote rural areas, some in semi-detached houses in the suburbs, and others in inner-city apartments. They may indulge in sexual orgies or lead ascetic lives of strict celibacy. Practices range from chanting, prayer, meditation or dance to ritual sacrifice. The size of the movement may be hundreds of thousands or no more than a handful' Some of the movements are actually or potentially harmful; others are perfectly benign. In short, almost the only generalisation that one can make is that they have been labelled an NRM or a cult at some time or other.'

How does she account for the numbers and for the variety of these movements? 'There have been waves of new religions throughout history. They very often occur when there is some kind of serious social change occurring, a change which could be due to war or famine or colonialisation. A change which means that there is not an easy fit between the traditional beliefs and the new state of society. There are always voices out there in the wilderness crying out 'Behold, this is the truth' but they are not normally heard.'

But doesn't whether they are heard or not have something to do with the charismatic qualities of the person who is doing the crying out? 'One of the things that I have observed is that the followers do just as much, in many cases, as the leader in creating unaccountable and unpredictable kinds of authority. It's often a relationship'

Becoming mildly frustrated at the manner in which so many of my straightforward ideas about cults are being swept away into the sociological undergrowth, I relapse into vulgarity. 'Yes, I'm sure there are some charismatic leaders who depend for their position upon complex negotiation with their followers, but let's face it, over the years we'e heard about a great many downright nutters who've visited their delusions upon vulnerable followers, as well as an army of charlatans who set up a new religion as a way to make a fat financial killing. You seem too easy on them.'

She stays perfectly calm. 'People do get very upset about the amount of money that Scientology takes, and people did get upset about the Children of God when they were doing their flirty fishing', going out and having sex with potential recruits to show how much Jesus loved them. People get upset about the Brahma Kumaris, or at least the husbands do when their wives join, because they have to become celibate. People get annoyed because of this group's attitude towards women, or this group's insistence that its followers renounce their family. But this doesn't mean that these people have been deluded. It certainly doesn't mean they've been brainwashed. There was one occasion when a man rang me up and told me he was very worried about his son. He was, he said, obviously in a very dangerous group. So I said, tell me about it. So he said, 'Well, since he joined he has stopped sleeping around, he has come off drugs, and he has cut his hair. I've been trying to get him to do that for years. He must be brainwashed.'"

I'm clearly going to have to try harder if I want Eileen to be more censorious. I try for the personal angle. 'Aren't there some groups you find especially distasteful?' 'Well, my partiality tends to be more for individual people. And the good thing. sociologically speaking. is that within one movement I can find people I really like and other who I really detest. That's quite helpful. It provides a sense of balance.' I tell her she hasn't answered my question.

For a few moments she reprises her 'good and bad in all worlds' answer but then unexpectedly confronts my point head on. 'I feel very uncomfortable with evangelic Christians. They are always chasing my soul and telling me to take Jesus into my heart. They are a bit creepy. I know some lovely ones and I do find it hard to understand why they believe what they believe. Sometimes I find it irritating and impertinent the way they go at me. The same with some of the human potential groups, where you say 'I'm sorry, I haven't got the time and I really don't want to do another course on human potential.'Can you afford not to do this?' they always say.'Yes,'I say.' can afford not to do this.ï' "

Are there any NRMs she particularly likes or admires?

'I've become very interested in what is happening to religion in the former Soviet Union. When it collapsed it produced an extraordinary opportunity for the mainstream religions to pull themselves up again. But it also provided an opportunity for the new religions. They really rushed in. They were handing out leaflets when the Berlin wall was coming down. All the rhetoric was about the new freedom of religion. But it wasn't long before the honeymoon was over and freedom became' my freedom not your freedom' The mainstream churches had a lot of difficulties. They had been repressed for many years. Their flock didn't know anything. Their priests were either very very old or very young. They were suspected of collaboration. And there were these foreign religions coming in and taking away their flock. So they started working with the governments to try and control alternative religions. And the ones who get particularly attacked are the Jehovah's Witnesses. They have been liquidated from Moscow. I don't mean killed, although there have been killings in the regions and beatings-up in Georgia. They really have suffered. And, of course, they also suffered under Hitler. They wouldn't salute the Nazi flag (or any flag) or say 'Heil Hitler' or bear arms or vote. They were prepared to die rather than sign a piece of paper. If you were a Jew or a gypsy in Nazi Germany there was nothing you could do. But if you were a Jehovah's Witness you could simply sign a piece of paper and get out. But they didn't. They chose to die. That is pretty fanatical' (I nod to show I've noticed the irony).

Does she still spend months at a time living with specific groups? 'Oh yes. Recently I've spent quite a lot of time with The Family. I'm also looking at the Moonies and adding a bit to my book about them. I'm fascinated at the moment with what happens to the second generation, with the children of the original joiners. You see, I found that a lot of the people I studied in the 1970s from the Unification Church, The Family, Scientology, Hare Krishna, now have kids of the same age as they were when they converted. And the majority of these children are leaving. So the brainwashing obviously wasn't very good. If they want to keep the children then they have to accommodate and make the distinctions less sharp. Make God and Satan less strong. Of course, once you lose these sharp distinctions, you get your schisms, with some wanting to go back to the pure and the fundamentalist.ï'

I'm a little surprised to hear her use the word ï'fundamentalist'. Isn't this a term that has been much abused in recent analysis? 'Yes. There are lots of ways in which it can be defined. It was used originally at the turn of the last century by Protestants in America who said there were certain fundamentals about Christian beliefs which had to be adhered to. The leading analysts of the phenomenon in the modern world talk about fundamentalism as the stressing of certain things in the past in order to fight modern secularism. But, of course, fundamentalists still employ modern secularist ideas. The Ayatollah uses cassettes and Bin Laden uses video and the Internet. The term gets misused. You can have fundamentalism without terrorism. The Children of God called themselves fundamentalists simply because they believed literally in the Bible and expect their followers to live and act as the disciples did. Once again, as is the case with the word 'cult' you have a concept which is used negatively. If a change of ideas is good then it's a case of 'conversion' If you think the change of idea is bad, then it's a case of 'brainwashing'"

My time is up. I know that Eileen is anxious to be elsewhere. She has generously agreed to this interview despite having to spend a great deal of time with her seriously ill daughter. I can't, though, allow her to go without asking about her analysis of the huge outpouring of grief following the death of the Pope. Would she see this as a sign of a universal yearning to get back to religion and abandon secularism?

I know as soon as I've put the question that my haste had led me to sound simplistic. She is comparatively gentle. ' think any generalisation like that has to be treated with a fistful of salt. What do you mean by secularism? There are so many different kinds. There is the hard atheist kind of secularism. There is the 'I think about God if I am getting married or there is some tragedy' kind of secularism. There is the secularism which is perhaps the only real secularism where you just don't think about religion. It is not a part of your life. There are more important things, like Manchester United. There's also the new spirituality, which looks for the God within rather than the God without. More eastern, more cyclical. It needs to be taken into account. In one survey 13 per cent who were not religious said that they considered themselves spiritual. They'd have been classed as 'secular' if they hadn't been given the opportunity to tick 'spiritualï'on the form.'

I suggest to Eileen that if they'd included 'sociologist' on the form as another sort of faith, she might have ticked that box. In a way it has become her path to the truth. ï'I do think that what I am doing is right in a methodological and perhaps in a moral sense, in that I think that the truth with a small 't' can be found, even if truth with a big 't' can't. So I am not agnostic about saying that this movement uses drugs or doesn't use drugs. It either uses drugs or it doesn't. That is something empirically capable of being investigated. But I also believe there are things sociology can't do. It can't say things like what is a real religion or what is a cult. It gives us a tool to understand but it is a limited tool.'