Bill Laar, education consultant and one of British primary education’s most popular speakers, sometimes uses this true vignette as a metaphor for the kinds of miracles wrought by schools. “The phone rang. I picked it up. And the voice at the other end said, ‘Hello, this is the head of John the Baptist speaking’.”

Even for a Catholic school that would be quite a feat. But not that much harder than much of what primaries are expected to do routinely.

Primary teachers, he says, have never before been so accomplished. But “to expect them to meet the wide-ranging demands of all children is an impossible requirement - and the impact can be disastrous”. Although the process of learning, and the skills of teaching, are extremely important, deep subject knowledge on the part of the teacher is essential if nine, 10 and 11-year-olds, with their various gifts in different areas, are to discover and develop their talents. We have never found out how far children can go, he says.

He argues that older children should be able to receive the same kind of interventions at sophisticated levels in subjects such as science or art that three to five-year-olds receive in good foundation stage classes. A reception or nursery teacher will watch the individuals in her class, and suddenly move in with the right question or suggestion to help a particular child make the next step. “How far can the modern primary teacher provide across the broad curriculum that intelligent challenge that takes children into deeper waters?”

Mr Laar was talking at a primary conference organised by the National Academy for Gifted and Talented Youth in the Midlands last week. It is a topic many teachers find awkward, and clearly Bill Laar did, too, for no one wants to diminish the specialness of every child. Nevertheless, this is part of the Government’s individualised learning agenda, and most teachers will agree that nurturing each child’s abilities is at the heart of their jobs.

Appealing as it is to believe that everyone is equally intelligent, this seems no more likely than the notion that every child could grow up to dance at Covent Garden or play at Wembley. But while not every child is a Mozart, had little Wolfgang been a peasant in the countryside, his whistling might well have been enjoyed by the local farmhands in the fields, but the rest of us would not know him today.

This is why the role of schools is so crucial, and why Bill Laar is especially concerned that the curriculum in so many schools is “diminishing” just as the breadth of the content that should be taught is stretching all the time. For instance, geography is hardly taught in primary schools, but the world is shrinking, and what happens in Beijing or Baghdad today can change our lives here in Britain tomorrow.

He worries that within a few years, pushed along by the workforce agreement and a national impetus to save money, we could have a situation where professionals teach the basics, and unqualified staff or outside specialists will teach the rest.

And like so much else, this would have the worst impact in the poorest areas. A school serving a run-down council estate will have more trouble finding literate and well-educated teaching assistants, and they are unlikely to have retired teachers, scientists, or artists living nearby to help with the broad curriculum.

Middle-class parents compensate for things schools can’t provide by buying them themselves: music lessons, dance classes, swimming, coaching.

But it goes even further than that, Deborah Eyre, director of the academy, told the conference. She described an interaction she had seen between a parent and small child in Oxford. The child ran into a puddle in her canvas shoes. Far from telling her off, the mother said: “Now wiggle your toes and tell me how it feels.” As the child was from a university family, Professor Eyre noted that the child will have been analysing from the minute she could speak.

Such unequal beginnings mean schools have to work harder. “You have got to be a talent detective, always on the lookout,” she said.

What gifted pupils dislike

* Being made to feel different

* Low-level tasks and time-filling activities

* Too much independent learning

* Not being told the lesson objectives

* Always having to help people who don’t understand

* Not being allowed an off day

Guidelines from a northern LEA