Britain in a flap as conservationists go to bat for . . . the common bat

The British, as is well known, fill their houses, gardens, cars, boats, caravans, cottages, countrysides, books, poetry, films, and paintings with pets - dogs, cats, birds, horses, guinea pigs, rabbits, hamsters, fish, and the like.

As far back as 1693, William Penn was writing that ''men are generally more careful of the breed of their horses and dogs than of their children.'' He may have gone a little far there, but he was onto something.

(Just to hand is more proof in the form of the latest book on Winston Churchill, this time by his daughter Mary. ''I like pigs,'' she quotes her father as saying. ''Cats look down on human beings, dogs look up to them, but pigs just treat us as their equals.'')

But has this island race at last gone too far? It has now taken unto itself the bat.

Greater horseshoe bats, Daubenton's bat, Natterer's bat, whiskered bats, Bechstein's bat, the gray long-eared bat, the noctule, the pipistrelle, the brown long ear, the barbastelle - it makes no difference.

All 15 species here are now protected by the full force of the law, to wit, clauses buried deep in 128 dense pages of legislation called the 1981 Wildlife and Countryside Act.

Provisions protecting bats took effect at the end of September.

Other clauses, protecting everything from the Glutinous and Carthusian snails to great crested newt and the black-veined moth, come into force every few months.

Britain rings with argument. Protecting moths may be all right, but bats have long had a public relations problem here. They get in the hair. They are seen as nasty, zooming things that hang eerily upside down in attics and dark places.

Once found in a home, they are often summarily dealt with by right-side-up Englishmen.

But now all has changed.

An Englishman's home may be his castle, but now he must share it with his bats. Molest a bat, even in his own attic or walls, and he is liable for a fine as high as (STR)1,000 ($1,710) per bat - and bats hang out in colonies of 500 at a time.

''We have courted publicity, in fact,'' remarked a bat woman at the government's Nature Conservancy Council. ''The act says people must notify us and get a license before doing anything in their homes that would kill or interfere with bats.''

An Englishman, a Scotsman, or a Welshman now insulates or remodels at his peril.

But how will the Nature Conservancy Council know who to prosecute?

''Ah, well, that's the thing, isn't it,'' said the bat woman. ''The act is to deter, in fact. That's why we want it known. . . .

''Under the previous Conservation Act of 1975, 21 wildflowers were protected. You couldn't dig them up without their owners' permission. But we only ever had two prosecutions.

''Still, . . .'' she brightened, ''the law is there, isn't it?''

Nor is it just for bats. The otter is now protected in Scotland. The red squirrel is conserved, and the sand lizard, the great crested newt, the swallowtail butterfly, the field cricket and the mole cricket, the wart-biter grasshopper, and the sandbowl snail.

Yet it is the bats around which most controversy flaps.

The council's bat man, Bob Stebbings, says that even the greater horseshoe bat and the mouse-eared bat, protected since 1975, are down to 5 percent of their number a century ago. More common bats such as the pipistrelle are down by almost 50 percent in the last three years alone.

New construction and urban sprawl rob bats of their roosts and feeding grounds. But the biggest culprit is chemicals lethal to bats regularly used to treat construction timber. More than 100,000 buildings each year are treated with such chemicals.

All of which explains the conscience-stricken tone of a 14-page color publication, ''Focus on Bats,'' and its enormous effort to make bats sound not only useful but also positively handy to have around the house.

Bats, the reader learns, do not chew buildings or paint. They don't even build nests. They simpy hang. Moreover, they eat wood-boring beetles. The message is clear: Harbor a bat and save your home.

Bats like to eat canned pet food, scambled eggs, and even chopped liver. They are also partial to mealworms.

Oh, well, the booklet concedes, there might be a few problems. Bat droppings are an excellent fertilizer and also build up into excellent insulation material , but you might want to put down a plastic sheet.

But many citizens remain unimpressed.

''Certainly, no one warned me (about) this Draconian law,'' thunders the Rev. H. A. Jennings of Bicker Vicarage, Lincolnshire, in a letter to the Daily Telegraph.

''Every year in my parish, between June and September, we fight a losing battle to protect our ancient and beautiful parish church against these filthy little creatures. . . . Fabrics, books, ornaments, and pews are soiled, . . . floors littered. . . .''