YES, it's another Carry On, the third in the series that has caused more laughter among more people in more British cinemas than any other in a month of fundays.

Having roared riotously through army barracks and hospital wards, the Carry On team of film-makers now breezes boisterously through the classrooms and corridors of the Maudlin Street Secondary Modern School.

There's much muddling at Maudlin, which isn't surprising when you look at the staff. This doubtful seat of learning has, as its head, muddleheaded William Wakefield (Ted Ray), with whom rests the responsibility of keeping not only pupils in order, but teachers too.

Dispensing scientific facts to scholars more interested in science fiction is Gregory Adams (played by Kenneth Connor). Bravely attempting to teach the Maudlin brats to speak like little ladies and gentlemen is English master Edwin Milton (Kenneth Williams). Putting the roughnecks through arms-raise and knees-bend when the art of self-defence would be more to their liking is Sarah Allcock (Joan Sims).

Soothing the savage beasts with music is Michael Bean (Charles Hawtrey), and preparing the youngsters to be citizens of the future with dispensations as to isosceles triangles and equilateral rectangles is roundfigured maths mistress Grace Short (Hattie Jacques).

The antics in which this erudite mob is embroiled concern the scholars' endeavours to give their head a bad name in the presence of important school visitors. He's applied for a transfer, and the Maudlin pupils hate the idea of losing him. School life couldn't possibly be such a huge lark under anyone else's headship.

The important visitors are Felicity Wheeler (Rosalind Knight) who's a Ministry of Education inspector, and child psychologist Alistair Grigg (Leslie Phillips). One look at Maudlin and Grigg finds it to be not only a mixed school, but a mixed-up one too.

The head has pleaded with his staff to bend over backwards to have the school running smoothly while the visitors are around in order to create a good impression that would speak well for him in his application for his transfer, but struggling to prevent chaos breaking out becomes a losing battle until the Maudlin academy of knowledge resembles a mad house.

In the midst of the uproar, luscious Felicity Wheeler wants to be Eve to science master Adams, but he, nervous little man, cringes at the very sight of her-until ordered to respond to her advances by the head who's determined to keep his visitors happy at a time when his chances of a transfer are in jeopardy.

Heading a long line of actors well known to radio and television audiences, Ted Ray finds himself in the company of two artists who have contributed to the success of his long-lived" Ray's A Laugh" radio series-Kenneth Connor and Rosalind Knight. In the numerous radio shows in which they've appeared since 1951, Connor has frequently got Ray into" hot water." But in Cany On Teacher, Ray gets his own back by producing as much trouble as Connor can cope with. Connor has appeared in all three in the Carry On series, as have Joan Sims, Hattie Jacques and Charles Hawtrey. To portray the attractive P. T. mistress in this latest romp, Joan Sims had her hair cut short and rinsed blonde, which contrasts effectively with her auburnhaired nurse in Carry On Nurse. Some women say, "change your hair colour and change your luck," but Miss Sims says, " change your hair colour and change your character."

What doesn't change in the Carry On series is the producers' formula for side-splitting laughs and roofraising merriment. Laughter is a tonic, and it's an excellent thing when a series like this can make millions happy.

Whether or not your school days were the happiest of your life, Carry On Teacher will provide you with one of your happiest evenings. It is, in short, a school" howler."