The final bell is ringing but the fat lady isn't singing. Not just yet. The children get off early on the last day, but for us teachers it is time for the annual gathering in a heaving, sweltering and emotionally charged staffroom. We are here to listen to the leaving speeches, including the dreaded retirement address from Bob in science. Colleagues claim they have seen him rehearsing in his lab late into the night.
There is general anxiety over just how much of the summer holiday this ceremony will consume, ever since the (possibly mythical) three-hour session back in 2003. The threat comes not from the leavers' own speeches (many of which are extremely brief) but from us, their line managers. We feel obliged to do justice to departing members of our team in the only way we know how - by talking a lot. This is in spite of the urgings from the top to "keep it brief". Sometimes "brief" means half an hour, featuring some dedicated verse, a department serenade and a PowerPoint biography.
Some younger colleagues struggle with the leaving speech ritual. They see it as something for the oldies to endure, rather like golf, National Trust membership and bingo. This is understandable. They are fresher and less institutionalised than the rest of us and usually have looser ties to the people going. They also have more compelling social commitments. Some of them would be in the pub by now were it not for the unpopular missive about this still being "directed time".
A few older colleagues may indeed be playing bingo in response to line managers' tribute speeches, although here it will be the more secretive and subversive variation - "Big Hole Bingo" (as in "He'll leave a."). We hear the stifled burst of triumph when a cardholder's row is completed - consisting of "going to miss her", "brilliant teacher", "the kids absolutely adored her" and "pastures new".
Listen out, too, for the surprisingly frequent "When he first came into the staffroom many of us mistook him for a sixth-former" and for those seemingly ubiquitous anecdotes about the departing teacher accidentally leaving a child behind on a field trip in Wales, leading students around the wrong part of Amsterdam or mistaking an Ofsted inspector for the man who fixes the photocopier.
Even more predictably, however, in the end everyone will be overtaken by the emotional significance of this event for certain people.
Schools can lose fine teachers and still thrive. But losing a great friend is another matter and we see tearful people each year for whom the afternoon marks the departure of a soulmate, someone who offered love and levity in a sometimes troubled and turbulent working life. The friendship may continue but it won't be the same.
When the retiring Bob does finally speak, all those fears of the rumoured epic prove unfounded. Instead we hear the most moving and inspiring words of the year - on why he has loved teaching and why education matters so much to him. By the end everyone feels profoundly pleased and privileged to have been there after all.
Stephen Petty is head of humanities at Lord Williams's School in Thame, Oxfordshire