People without children in a school production are seldom expected to enjoy such an enterprise, much less attend it. However, thanks to Peter Maxwell Davies' ingenious writing, absolute strangers could walk in on his opera "Cinderella" and have a grand time. In the tradition of the British Christmas pantomime, Davies has taken the sugar out of the familiar story and put spice in its place.

One of a cluster of children's operas that have recently come to Washington, Davies' is the only one done by children. Given last night's delightful performance at the Sheridan School, which was the opera's American premiere, that difference must be counted a big plus.

He not only gives the young cast--in this case they were fourth- through eighth-graders--easily manageable material, but he also makes room for the freshness of their viewpoint within the opera.

To those who know Davies as one of Britain's major avant-garde composers, the accessibility of the work will probably come as a surprise. It was first presented in 1980 by schoolchildren of the Orkney Islands where Davies now makes his home.

In the story according to Davies, Cinderella leaves home in order to earn her living as an au pair for an impossible trio of spoiled females. Their mother begs them to behave so that Cinderella will not have an expensive nervous breakdown like the six previous au pair girls. Cinderella gets to the ball through the magic powers of the cat, who is "the 7th daughter of the 7th daughter of a special kind of cat." At the ball the prince falls for Cinderella while the three ugly sisters, Medusa, Hecate and Dragonia, are wooed by three heads of the armed services with such names as Lord Delta-Wing Vertical Take-off and Field Marshal Sir Wellington Bombast Blimp. The sisters do not even really want the prince. When he comes with the magic slipper, their heartthrobs arrive with, respectively, a wig, a set of false teeth and an oversize pair of bloomers. Everyone goes off happy.

For this Marx Brothers libretto Davies has devised music characterized by strong rhythms and simple melodies well within a young person's grasp. Keys, in the traditional sense, are missing, but the lines move with such a natural force that dissonances are never a problem. By cleverly distributing small motifs to a variety of instruments, which include recorders, xylophones and glockenspiels, Davies has also created an appealing orchestral accompaniment that can be played by children.

In addition Davies brings the frank world of children into the libretto by allowing for, indeed encouraging, local adaptation at certain points. For example, Cinderella has the onerous chore of changing TV channels for the squabbling sisters. In the original British version one of the sisters says that she wants to watch something cultural, like "The Comedy of Errors." Following Davies' advice, the American sister last night adapted to her locale, saying, "I want to watch something cultural--like the 'American Bandstand with Dick Clark.' " Another inspired suggestion--that a sister role could be sung by a boy whose voice has changed--was also followed last night to marvelously funny effect.

Music director Nettie Ruth Bratton deserves much credit for bringing the opera to Washington. Let us hope she has started a national trend. The performance will be repeated tonight at 8 and tomorrow at 3.