Yes, that frail offspring from an unlikely coupling - Margaret Thatcher and her beaming education secretary, Kenneth Baker - is now 20 years of age.

In celebration, I’ve treated myself to a remaindered copy of Lord Baker’s autobiography, The Turbulent Years, and it’s duly been delivered in a nondescript paper wrapper. Already it feels well worth the 50 pence it set me back.

You might assume that, as a former education secretary herself, Mrs Thatcher would have kick-started her premiership in 1979 on a mission to implement a new curriculum. Not so. Her early incumbent, Sir Keith Joseph, tinkered with vocational education and upset the unions, but left an uncluttered in-tray. Lord Baker recalls “something about violin lessons”, but nothing of any urgency.

This fits with the apparent other-worldliness of Sir Keith, who is reported once to have been given a tour of some television studios - in the days when the bastions of broadcasting were being nudged aside by upstarts such as GMTV and Sky. Gazing at the production gallery, cameras and banks of flickering video images, Sir Keith allegedly said: “It’s all very interesting, but do you think it will catch on?”

So, with a hands-off approach from Mrs T (“Read yourself into it, get into it, and come back to me in two months and tell me what you’d like to do now”), Lord Baker did just that. And what he came back with developed the uncontrollable urges of the monster constructed on Dr Frankenstein’s slab. Teams of academics and teachers carved up the universe into concepts that have formed the framework of how we do things now in English schools: programmes of study, attainment targets, key stages - these utilitarian terms would become our lingua franca.

From the outset, the project began to totter, stifled by its bloated self-importance and sniped at by media pundits. Subsequent education secretaries tinkered and trimmed, set up working groups, and drafted in heavyweights such as Sirs Ron Dearing and Mike Tomlinson to create a curriculum fit for purpose. Every new version of the curriculum was published in a slightly more garish shade of yellow - an appropriate metaphor for the increasing sense of jaundice felt by many teachers.

So here, in the chilly early summer term of 2008, teachers find themselves granted an extra training day for the sheer amount of change at key stage 3, the new vocational diplomas to be taken at 16 and 18-19 and at A-level. What is striking is how we accept this curriculum convulsion as the norm.

As ever, Sir Michael Barber’s research into the world’s most successful schools is illuminating: “In Finland, the fact that the national curriculum specifies only general outcome goals, rather than the path by which to attain them, means that teachers in schools have to work together to develop the curriculum and instructional strategies tailored to the needs of their school.” (How the World’s Best-Performing School Systems Come out on Top; McKinsey, 2007.)

And that’s the price we’ve paid for the curriculum straitjacket conceived in 1987. Because while it deserves a muted birthday party-popper for ensuring that children don’t move across the country and lose all momentum, such prescription comes at a cost. We’ve allowed ourselves to focus on the “what” of the classroom and not the “how”, to be duped into the notion that teachers - like postal workers - “deliver” things like lessons and the curriculum.

Now there is an opportunity to reclaim the curriculum and focus on what effective teachers do to motivate, inform, and raise standards. That comes from great teaching, skilful engagement with young people, and expectations that are higher than they themselves often have.

And that’s not something you can pick from a file on a shelf.

Geoff Barton, Head of King Edward VI School, Bury St Edmunds.