My washing machine finally gave up the ghost last week, so I was forced to use the only launderette within a five-mile radius. Laundry safely deposited in one of the extortionately priced machines, I nipped to the newsagent next door to purchase a paper.
Sporting baggy linen trousers and matching T-shirt combo in bilious green with hair speared haphazardly on top of my head and a huge pair of dark glasses, I had imagined I was suitably incognito. But no such luck.
Just as I had clearly enunciated my desire for a packet of Benson amp; Hedges, I heard the dreaded "Miss! Miss!". Turning around, I encountered two Year 9 pupils from one of my local schools. They, of course, like most teenage girls on a Saturday afternoon, looked immaculate, like models for Top Shop.
"All right, Miss?" they drawled as they drank in my dishevelled appearance and beadily eyed my tobacco contraband.
"Hi girls!" I gibbered in reply, fighting the impulse to protest that the cigarettes were not for me (actually they weren't - they were for my husband - honest).
Fine, it wasn't as if I were dressed like a hooker, peddling crack on a street corner, but I hadn't felt this jumpy since I'd been caught smoking in the boys' changing room by my headmaster. And that had been as a pupil 30 years ago.
Obviously at school one has to at least make an effort to present a professional image: smart clothes, tidy, non-weird hair, calm and pleasant demeanour. You really get into the part. Your character wouldn't smoke or drink - they write poetry while listening to Mozart and sipping fizzy mineral water, of course.
At one school I worked in, I was able to take the "gels" outside on fine days, where we would sit under the shade of a huge tree and read aloud from Pride and Prejudice. Totally dreamy and idyllic, eh? So it's no wonder if I come over all Victorian governess from time to time.
Of course teachers are role models, in a sense. From Mr Chips to Miss Jean Brodie, they are there to inspire and help shape young minds. But although Miss Brodie had a keen sense of fashion, I can't imagine Mr Chips modelling denim hipsters and a check shirt on his days off.
When I was a pupil, it seemed totally incongruous to imagine teachers having "normal lives". I'm sure there are still some pupils today who imagine that when the bell rings at the end of the school day, we switch off the lights and climb quietly into the cupboard at the back of the room.
Perhaps it's all about mystique. I know that there are perfectly competent teachers out there who are barely older than their A-level students and who regularly meet up with their pupils in clubs and enjoy social networking with them on Facebook. But some of us like to keep our professional and social lives distinctly separate. That's not to say we aren't pleased to run into past (or present) pupils and find out how they are doing, but it would be a boon if we could choose when.
Why do random encounters never happen when one is looking one's best? Take Tariq. I was bleary-eyed from far too many glasses of wine and my magenta face was clashing violently with a red rugby shirt. In my defence, it was a celebration meal in a curry house in town towards midnight after a successful Wales International match.
Of course that was when a vaguely familiar face fuzzily swam into focus. "Hello Miss!" With super-human effort I snapped into "teacher mode" while Tariq (thankfully I remembered his name) told me all about his GCSE results and how he was getting on. I had taught him German and he was proud to inform me he had obtained a C in his German GCSE and that he was now working as a commis chef in his uncle's restaurant.
I congratulated him and complimented him on the curry. He left me with a mischievous grin on his face, saying, "Nice to to see you Miss, you're looking well!" I couldn't help wishing that I'd been a picture of elegantly coiffed sobriety rather than slightly squiffy with traces of korma around my mouth. Still, at least he sent a basket of complimentary popadoms to the table.
So teachers beware ... Just when you thought it was safe to put out the rubbish in your nightie or open the door with your curlers and face pack, a "Hello Miss!" moment may be just about to strike.
Jo West is a supply teacher based in Cardiff.