London — By rights, the fields and woodlands around the American airbase at Greenham Common should be deserted. Early last month, the British authorities made their most determined effort yet to evict the women who for 21/2 years have camped outside Greenham's nine-mile perimeter fence in a protest against American cruise missiles in Britain.
Because Greenham is the symbolic heart of the British peace movement, the April evictions were expected to deliver a heavy blow to the whole Campaign for Nuclear Disarmament (CND).
It has not turned out that way - either for the Greenham women or for the CND.
If the events of the past few months have proved anything, it is that the Greenham Common women and CND have an uncanny ability to survive against all odds. They have done nothing to stop Mrs. Thatcher's government from going ahead with its defense policies as planned. They have, however, managed to transform nuclear weapons from a side issue into the subject of national debate.
All previous efforts to move the Greenham women have come to nothing. In the most recent attempt, the forces of law and order were confident that their timing was right.
They calculated that the women's morale would be completely sapped after having failed to prevent the arrival of the missiles last November, and having just emerged from a long, hard winter in primitive conditions.
Although bailiffs, backed by hundreds of police, evicted all six Greenham encampments early April 4, by the following morning, the women had moved back to the cleared sites in greater numbers than ever before. Defiant notices went up on trees and bushes, proclaiming: ''Business as usual'' and ''we're here to stay.''
As one of the protesters remarked last week: ''We're going nowhere, until the last cruise missile has been removed from British soil.''
The latest spate of evictions has also drawn dozens of extra supporters to Greenham, and the women have devised fresh tactics for defying the bailiffs who make almost daily visits. When they are seen approaching, the women throw their cooking utensils and sleeping bags into cars and vans parked nearby, go for a little drive, then calmly set up again once the bailiffs have gone. One resourceful protester has built her makeshift home on a trolley, which she can wheel out onto the road and out of harm's way until the raid is over.
An extensive network of well-wishers keeps the cash and food parcels flowing in. Anything the bailiffs seize is swiftly replaced. The evictions have now degenerated into a game of cat and mouse, with no end in sight.
For almost a year now, ever since the British public so resoundingly rejected the Labour Party's unilateralist defense policies at the general election, the peace movement has been pronounced dead at regular intervals by a largely hostile press and a Conservative government committed to NATO membership and multilateral disarmament.
So confident was the government of its imminent demise, that back in September a special unit which had been working under Defense Minister Michael Heseltine to counter CND propaganda was dissolved - on the grounds that it had accomplished its task. Mr. Heseltine said he was confident people would forget all about the cruise once it was here.
But now, even CND's most vocal opponents, a movement called ''Women and Families for Defense,'' concede that it is still very much alive and kicking.
A spokeswoman for the organization said this week: ''I simply don't believe they (the CND) are going to go away. And meanwhile we're fighting an uphill battle against the complacency of the silent majority. The danger is, that unless people stand up and show they support the government, no one will get to hear both sides of the nuclear debate.''
Far from falling off since the arrival of cruise, CND's national membership stands at an all-time high of 94,000. Its organizers claim it is growing at a steady rate of 400 each week.
''We are now extremely broad-based,'' says CND's general secretary, Msgr. Bruce Kent.
''We are penetrating areas of thinking in this country that simply weren't with us before. Our main task now is to continue what the Dutch have called 'the long march through the institutions.'''
The movement's organizers do however recognize that with cruise here, the focus of their activities will have to change.
They are already thinking ahead, to the future of American bases in Britain and to ways of stopping Trident - the American submarine-based missile system that is scheduled to replace Polaris as Britain's next independent nuclear weapon.