Helping restock a London library with Americana

A unique group is working to rebuild the most comprehensive collection outside the United States of literature relating to American life. The venerable British Library in London has long housed an extensive collection of American books, periodicals, pamphlets, and newspapers. But bombing raids during World War II destroyed much of it.

Now a latter-day Marshall Plan has begun to replenish the collection. Established three years ago by a group of dedicated American bibliophiles, the American Trust for the British Library is beginning to bear fruit.

Already some material - from 57 volumes on glass technology to a complete file of the Washington Star - has been copied and delivered to the library with the aid of more than a $1 million in contributions from foundations and associate members in the US.

''The British Library's American collection is a treasure store of scholarship,'' says Douglas W. Bryant, trust executive director. ''By making it more complete, we are further cementing that most important of ties - the Anglo-American bond of understanding.'' He also cites ''an unprecedented growth in the study of the US throughout Britain: in its history, its people, its culture, its technology, its place in the world - in short, all that makes it unique among nations.''

The origins of the American collection are traceable to the partnership of a naturalized Briton from Italy and a self-styled ''Green Mountain Boy.'' In 1846 Sir Anthony Panizzi was granted a (STR)10,000-a-year stipend to purchase ''foreign and antiquarian materials.'' He commissioned Henry Stevens of Vermont to ''sweep America'' in search of additions to the American collection. Some 100 ,000 volumes were found, but later the collection fell into relative neglect. The present effort is designed as much to fill the gaps created during this period as to replace materials lost in the war.

The project has spurred the reproduction of rare and deteriorating periodicals and books. At little cost, US libraries are given the photographic masters of documents after they are used to make a copy for the British Library.