Colchester, England — On the edge of the suburbs of the ancient town of Colchester, in eastern England, is a lane that leads to a strikingly pink cottage that happens to house the most dangerous woman in Great Britain.
At first glance it is difficult to see what could possibly be dangerous about a woman of such grandmotherly appearance. She is dressed in a flowered skirt and pale green blouse, and she has just been out among the flower beds in her large sweep of a garden, surrounded by various red-haired grandchildren.
But this woman is Mary Whitehouse, and as everyone in Britain knows, Mrs. Whitehouse is called ''dangerous'' by her critics because in the early '60s, as an ordinary housewife and schoolmistress, she decided to make a nuisance of herself by standing up for what she believed.
She felt then - as she does now - that extremes of obscenity and violence should not be shown on television, and that if they were, Britain would become a more violent society and sexual morality would be undermined.
In the 19 years since she first made the decision to stand up for her beliefs , Mrs. Whitehouse has made it her business to confront those in authority who are tempted to accept passively that obscenity in the communications media is a necessary consequence of living in a free society.
She has been behind formidable victories on several test cases involving obscenity and was instrumental in gaining the passage of a strict antichild-pornography law in Parliament in 1978. Her work was given the official stamp of approval when she was honored by Queen Elizabeth II in 1980.
The most dangerous woman in Britain is also controversial. Her name has certainly become a household word, but the meaning of that household word varies considerably from house to house. Mary Whitehouse has been the target of ridicule and even physical threats from those who fear she advocates censorship and repression; and she believes her image has been distorted by the media into a threatening caricature of moral severity.
This September, a revised and updated version of her autobiography entitled ''Mary Whitehouse: A Most Dangerous Woman?'' is due to be published in Britain. There are plans to publish it later in the United States.
On a recent warm day, Mrs. Whitehouse spoke in her informal living room of the challenges that lie ahead for her and her organization, the National Viewers' & Listeners' Association, which she founded to promote decency in television.
She says a major new concern for her is to help bring into effect regulations to govern the content of videocassettes available for home use. An important related project is to establish obscenity guidelines for the cable television industry, still in its incipient stages in Britain.
''The problem is that pornography on video is piggybacking on the coattails of a respectable industry that could give a lot of joy and pleasure to people,'' she says in a voice that expresses weariness with the prospect of another battle against the exploitation of the media. ''The heart of our concern is what comes into the home.''
''We've never legislated for anything like this because we never ever thought of the possibility of such matters. It's flooded over us unawares, and nobody is able to contain it,'' she observes.
Particularly troubling to her at the moment are three videocassettes that have appeared on the home market. The films, called ''nasties'' in the video trade, are much more violent and realistic than what appears in cinemas, she says. Called such things as ''The Driller Killer'' and ''Cannibal Holocaust,'' they represent a new level of depravity, she believes.
The films have been independently brought to the attention of the police and are currently before the director of public prosecutions, who is due to act on them soon. ''If the director of public prosecutions does not take action over these three films, we will raise the matter with the European Court of Human Rights,'' she asserts.
If the films are prosecuted, it will be the first action in Britain against a film featuring ultrasadistic horror, rather than pornography.
''The people in the video industry are very concerned about this exploitation of their trade,'' she explains. ''And I believe this will be a test case that will form the basis of legislation of video.''
Mrs. Whitehouse emphasizes that it is very important for legislation to be made governing video and cable as soon as possible. ''If cable, especially, is allowed to get a foothold without proper legislation to prevent abuse, it will be very difficult to correct the situation afterward,'' she insists.
''The people who have an interest in video - whether it's personal or financial or whatever - have access to the media, so you get this idea that anybody who is anxious that there be some kind of control over this is some kind of fuddy-duddy, some kind of awful, extreme right-wing censor.''
Although she is proud of her victories, Mrs. Whitehouse does not feel she can relax in the assurance that her work is nearly over. She says that hard-core pornography is worse than ever: ''If one could have gone back 10 years and brought society face to face with what's now coming out on video, I think there would have been a tremendous explosion of public anger.''
She sees the answer as specific obscenity laws, such as have been passed in Atlanta under the direction of Hinson McAuliffe, solicitor general of Fulton County. Courts have argued over the years that it is impossible to specify what is obscene and what is not. Mrs. Whitehouse disagrees, saying that pornographers have been given too much leeway to influence the public.
But ism Mrs. Whitehouse a fuddy-duddy? And if her vision of society and the media came true, would it be lifeless and repressive? She arges that it would not. ''I would be the last person in the world to say that we must have programs with nom manifestations of sex or violence. What we're on about is howm they are dealt with.''
She believes that many of the people who are suspicious of her motives do not understand the firm Christian faith that motivates her. ''Looking back, the way we were ridiculed up hill and down dale, the attempts that were made to silence us - every kind of attempt you can think of - the reason we attracted the ridicule is that they jolly well knew we were talking sense. As the years have gone by it's come to be seen that what we said is more and more true,'' she says.
The chimes of the living room clock struck 1 o'clock; it was time to eat. So the most dangerous woman in Great Britain picked up a large kitchen knife and, brandishing it, went out to cut some home-grown produce for her family's lunch.