I discovered that the term “fast food” applied only to its taste and texture and not to the speed with which it was served. A magician was employed to entertain the customers while they waited and to distract them from looking again at the inflated prices and deciding that they really wanted to eat elsewhere.

When solemnly told, after he arrived at our table, that black was the favourite colour of the moment, the magician promised to change a blue hankie to a black one. Rather impressively, the blue hankie disappeared from his hand in a puff of sparkling dust and emerged in an unmistakably identical hue from a purse sitting on the table. The loud reaction from my darling boy was: “It’s not black I Rubbish!”

I am experiencing the same sense of unfulfilled expectation about the post-McCrone agreement. I clearly recall the magic words “substantially increased salary” but have only a hazy recollection of other promises made at the time that were going to transform life and make it so much easier for all of us in the primary sector.

My extra salary has long ago been consumed by my lifestyle, converted into movable estate or just plain squandered and now, three years down the line, I find myself dealing with a pile of ordure in relation to the rest of the post-McCrone package.

Not in a puff of sparkling dust, a spreadsheet landed on my desk, provided by the local authority to help me decide how to manage the reduction in teachers’ class contact time in August. I have pondered over a line of numbers including figures such as 0.05 FTE, 0.81 FTE and 0.23 FTE and am none the wiser for it.

In the absence of an accompanying explanatory note, I found myself comparing what we appear to have been allocated in additional staffing against other schools. I didn’t understand what we were getting, why we were getting it or what we were going to do with it, but I was damned if we were going to get less than anybody else.

Apparently, all I had to do was work out how to ensure that teachers have the correct amount of non-class contact time on a pro rata basis for the amount of time they are in the school, remembering to build in time for handover between lessons, for liaison, for personal time and for travelling, and then apply it to a workable timetable, drawn up in blocks of 45 or 90 minutes.

We considered several models. We toyed with the idea of using the time for visiting specialists’ lessons to free teachers from class. This didn’t seem viable when we realised that the vagaries of specialist teacher provision and attendance could soon cause a backlog of non-class contact time.

What about having a member of staff elected to teach a subject in Primaries 4-7 to release other teachers? Which subject could stand alone for one-and-a-half hours a week and would not skew the balance of the curriculum?

Volunteers to become peripatetic teachers of a combination of information and communications technology and religious and moral education please form a queue here.

We looked at amalgamating several approaches to provide enough non-class contact time. We talked about using some visiting specialist time, combined with time for teaching French and time provided by an additional teacher.

We identified the teachers involved, multiplied by 1.5 hours, converted it to a full-time equivalent figure and then added on some more time to take account of variables, converted it back into 45-minute blocks and arrived back at the number we first thought of.

I have not worked out how to pull rabbits from the hat in the shape of teachers available and willing to provide non-class contact time for their colleagues. The one thing that I am very clear about is that the person providing the cover will never be me.

What seemed to McCrone to be a magic idea at the time is proving to be less than enchanting in its unfolding.

Compared to the arithmetic for allocating non-class contact time, the working out of figures for an actuarially reduced pension begins to take on tremendous appeal.

Joan Fenton is headteacher of Dyce Academy, AberdeenIf you have any comments, e-mail scotlandplus@tes.co.uk