Appearances count and, love it or hate it, people in all walks of life are judged by how they dress. How you present yourself is very much part of what you are.

Depending on where you are and what you're wearing, your clothes can command respect or derision. This is as true of school as it is of any other place.

Geraldine Keegan, principal of St Mary's College, Derry, is a long-time advocate of the importance of teachers' dressing well at school.

"Teachers are professionals carrying out professional jobs," she says. "Our style of dress should reflect our role. How can we expect students to be well dressed if we don't insist on very high standards for ourselves? "Dressing well shows respect for the people you are teaching," says Keegan, who is a pro-vice chancellor of the University of Ulster. "If you come into class sloppily dressed you're sending out the message that your students are unimportant and that your own role is unimportant. In such situations teachers don't receive the respect they deserve."

She believes that people are judged by their dress - "and there's nobody who will do that more stringently than students. This is constantly brought home to me - they constantly comment on what we wear."

Students and teachers at St Mary's College all have good dress sense, their principal says. "Substitute teachers often tell me that they feel they have to dress up when they come here." Students, too, get compliments from visitors. "We have almost 1,000 girls in the school and it's very rare to find anyone not wearing the full uniform, including the tie." New teachers are introduced to the school's dress code, which includes a ban on jeans. "I believe they should avoid wearing clothes that are designed for leisure activities."

At St Mary's, male staff are expected to wear ties, while female teachers wear well-cut tailored trouser or skirts. In most instances jackets are more appropriate than knitwear, Keegan says..

In recent years, St Mary's has undergone a name change. Students voted to change the name from St Mary's Secondary School to St Mary's College. The non-selective school lies in the heart of the Creggan estate, one of the most socially disadvantaged areas in Ireland.

Keegan came to St Mary's as principal back in 1987 at a time when the school was undergoing great change. Since then St Mary's has won 13 national and international awards, including the Investors in People Innovation Award 1997, which is open to a variety of institutions including the corporate sector. Good dress sense, Keegan asserts, is part of the culture and ethos of the school. "I honestly believe that it reflects the morale of a school. I've been in schools where morale is very poor and I've always felt that the dress sense of the staff reflected this. You can pick that up in any organisation."