Give Madonna room to breathe

Masaccio, a youthful genius presiding over the maturing Renaissance in 15th century Florence, born six centuries ago this year and dead at 27, is celebrated by the National Gallery with an exhibition centred on his Madonna and Child.

This was at the core of a complex altarpiece painted between February and December in 1426, designed for a new chapel in the church of the Carmine at Pisa. Dismembered late in the 16th century when the church was rebuilt, several of its painted panels are lost, but the gallery has brought together the 11 surviving panels in an attempt to suggest how the polyptych may originally have looked.

No wings of this altarpiece survive and the reconstruction is an incomplete hypothesis, but if in our imagination we patch into this diagram the 11 panels that are now hanging on the walls of room one, we have at least some sense of how the altarpiece may have been designed by young Masaccio, then only 25. It is in part a Gothic survival, in part astonishingly far-sighted.

This is, of course, an exercise in scholarship designed for the delectation of art historians not for the general public, for whom the National Gallery, in mounting it in room one, shows utter contempt. This masterpiece, admired in its day, admired by Vasari, the father of art history, shortly before it was dismembered, painted by an artist whose influence remained profound throughout the Renaissance, even on Michelangelo, its panels brought from Berlin, Naples, Pisa and Los Angeles in an exercise that can never be repeated, so terrifying are the risks, is in a room too small for it.

I went to see it in the first hour of public access, and the public was there in such uncomfortable numbers that the smaller panels were virtually invisible and the atmosphere as foetid as the Black Hole of Calcutta.

It was madness to put these precious fragments so cheek-by-jowl in so small a room and assume, as a gallery spokesman said, "that the public would not be interested". It is not the business of the gallery to be so contemptuous of us, to assume that we know nothing of so rare a painter and have no interest in him. The gallery should at once make amends by moving the exhibition to a much larger space where this marvel of perspective, of form, volume and expression, of tenderness and grandeur, can be properly and comfortably contemplated and appreciated.

? Masaccio: the Pisa Altarpiece is at the National Gallery until 11 November.