It is 8.50am and I have been up half the night with a hacking cough. Despite this, I am as usual wearing my happy, smiling face. Like Eleanor Rigby's, it is one I keep in a jar by the door, although I do admit that on days like this it's not always easy to get the bloody lid off.
As the children pile into class, their faces made raw by a biting November wind, I switch my smile to full beam. But by half past 9 my facial muscles tire and I step down a gear to a cheerful countenance with the occasional grin of encouragement thrown in for good measure.
Wearing a happy, welcoming face is a fundamental part of being a good teacher. Your face is the first point of contact and it needs to tell the children loud and clear that no matter what happened at home or on the estate overnight, it won't happen here. This classroom will be a warm and cheerful place, and this teacher will keep smiling even if he gets facial cramp.
Of course, my smile is over-exaggerated. This is to make sure that those children who can't tell a digraph from a diphthong (whatever they are) can easily decode it. But therein lies a problem. Smiles can be a bit like unsolicited calls from people desperate to reclaim mis-sold payment protection insurance for us. After a while they become downright annoying.
Anyway, it's not only about children reading my face; it's also about me reading theirs, and like the books on our shelves, children's faces make for some interesting reading. This morning we have multiple copies of Mr Happy and Miss Giggle, numerous action adventures, a couple of undernourished Dickensian orphans, one Horrid Henry and a few that are several pages short of a full story.
And then we have Danny, whose face isn't so much an open book as a "Keep Out" sign, and whose whole demeanour is like a top secret report from RAF Fylingdales. This morning there are more red lights flashing than a stag do in Amsterdam and his front cover states quite clearly that this is your one and only four-minute warning of a devastating nuclear attack.
Following a well-rehearsed drill I assess the situation and call for backup. The immediate danger is quickly defused by our highly skilled behaviour support team (think Charlie's Angels meets French and Saunders). No one dies, there is no disruption to learning and collateral damage is minimal, being confined to the walls, doors and furniture of our "nurture room".
In fact, the only casualty is Danny himself, who for most of the morning sits under a table repeatedly banging his head on it. But it doesn't last forever, and by mid-afternoon he has caught up with his work and is keeping calm by making complex laser weaponry out of Lego. Before the end of school he is back in class listening to the story.
Danny's mum picks him up from outside the school office. She is half an hour late again because she missed the bus ... or she fell asleep on the settee ... or there were these flying elephants. As usual she is slightly the worse for drink ... and slightly streaked about the make-up ... and slightly bruised about the face.
You ask if everything is OK and she nods in reply, but there is a remoteness about her that reminds you of a military listening station on the North York Moors. And her face says only one thing: Keep Out!
Steve Eddison is a key stage 2 teacher at Arbourthorne Community Primary School in Sheffield.