Light streams through the designer stained glass windows on to chairs where gently-ageing trendies drink cappuccino and discard newspapers in favour of conversation. The mood is mellow in Glasgow’s Cafe Gandolfi, the conversation at one particular table less so. Here, actor, singer and comedian Elaine C Smith is working up more froth than is on her coffee.

The ire of this former teacher is aroused by education officials, teachers and teacher training college lecturers in Scotland who send their children to private schools. “They can get a cheque book out and buy a superior education for their kids. They’re saying, ‘The state system is good enough for your child but not for mine’ - it’s sickening. If they don’t believe in state schools, they shouldn’t take a wage from it.”

A woman at a nearby table looks intently at her menu but seems to be more interested in what Elaine will say next. She is not disappointed. “If you opt to take a student grant and then take a wage from a private school, you should pay the grant back. I’m a fascist on this subject.” After dining on this conversation, the fare of Cullen Skink or North African casserole seems uncharacteristically insipid.

Miss Smith wonders if she has voiced her views a tad stridently. But the gleam in her eye and the words: “That should get them going” suggest that a large part of her likes nothing better than to stoke up a stushie OK. Half-measures seem foreign to her. She embraces the cafe owner and friend who approaches our table, but it is an earthy hug rather than a luvvy kiss.

In common with most Scottish actors, Elaine C Smith hails from a streetwise background and, although tennis is a major hobby and one three-year-old child is in a private Montessori because of the absence of state nursery places in Mount Vernon, she seems to remain fairly in tune with her roots. They come to the fore in conversation on and off-stage. She laughs at the recollection of watching a Celtic Rangers match with fellow actors during the interval of last year’s Much Ado About Nothing at the Edinburgh Royal Lyceum, in which she played Beatrice - “Burley’s scored!” was her sotto voce remark to another actor in the wings as she went on stage to launch into a soliloquy.

No danger then of Miss Smith, 39, forgetting the four-year period in her early twenties when she was a teacher at the chalkface in an Edinburgh secondary and associated primaries in a very mixed catchment area. She remembers many colleagues at Firrhill High who made tea break something to anticipate. Miss Smith, the Motherwell-raised drama teacher who walked into the staff room in her flying suit, trying to sell copies of the feminist publication Women’s Voice, was the target as well as the perpetrator of many wind-ups. Her tribute to the great glorious talent of former colleagues to make others laugh, makes you wonder whether there is a vast pool of comic teachers out there, who could also make it on more than the school stage. That thought bubble is burst before it has time to get carried away.

“No one can moan like a bunch of teachers,” she claims. “Actors can moan but teachers are Oscar-winning. They moan about the kids, the school, the heidie. It is essential for a teacher to have a sense of humour. If you don’t, forget it.

“When I went in, there were lots of young, articulate, clever people going into teaching. That youth is not going in now. I left before teachers were really hard-hit and despondent, before constant criticism and increased workload got to them, their sense of hope and vocation. They could become very negative and soulless.”

Despite her sympathy for current pressures on the teaching profession, the suggestion that significant numbers currently in the profession are dull, ageing and second division, leads me to wonder whether someone somewhere in the room will overturn their designer chair and pour their cappuccino over her. But then, she gets onto safer ground by confessing envy of current teachers: “On the first day I worked as a teacher, I remember thinking that nothing had ever felt so right. It was totally fulfilling. I miss the contact with kids and the feeling that you were doing something that matters.”

She speaks with passion of teachers’ ability to turn a pupil round, drama teachers in particular, of course. This graduate of the Royal Scottish Academy of Music and Drama believes that drama, properly taught, should be a core subject since it helps children to become more confident, articulate, imaginative and assured - skills which have an impact on their performance across the curriculum and can build up their personality.

She remembers the electricity of a lesson in which, after related work on McCarthyism with the modern studies department, children improvised their own trial and ending to The Crucible. She remembers after another lesson in voice and movement for what she terms “third year mental cases”, a colleague coming up to her and saying “I never thought any of those kids were capable of that”.

She remembers a girl looked after by foster parents, then rejected at 11 and placed in a children’s home, who kicked open the classroom door to her first drama lesson - one small indication of an angry powerful personality which meant that for a long time every lesson had to be taught through her. If she was bored and bolshy, the lesson collapsed. Within the boundaries of a pupil-teacher relationship the new girl and the new teacher travelled three-and-a-half years together, at the end of which the former was neither an angel nor a Meryl Streep, but someone whose behaviour had modified to the point where the school rewarded her with a year’s exchange visit abroad. Not that Miss Smith claims credit for this or claims to be infallible.

She groans at the recollection of her first teaching practice when she decided to tap into kids’ appetite for blood and gore by choosing the story of Sweeney Todd, a big musical at the time. To help matters along she brought a large implement from home and, holding it aloft, cried: “This is the actual knife!” The dramatic effect was reflected most vividly in the countenance and cardiac rate of the class teacher.

Like all drama teachers, she says, she had to fight for respect from colleagues in other departments who assume that behind closed doors the classes occupy themselves by pretending to be trees and teapots. It was while expounding on the plight of drama teachers at a meeting of the Educational Institute of Scotland, that she met economics teacher Bob Morton who is now part of her management organisation, her husband and the father of her two daughters.

Elaine C Smith says she loved teaching and misses it. But with commitments this year including a new television series, a seventh series of Rab C Nesbitt, a book, a children’s TV series Hubbub, a panto and negotiations with other parties to set up a country music station, could she ever contemplate making a comeback in the classroom?

“I don’t miss feeling that knackered,” she says.