The floating glass walls illusion

The floating glass walls illusion
There was a purpose to the greenhouse wall: to bring light to a choir of monks up half the night by candlelight in the darkness, and to illuminate the liturgy of the Mass / © ALAMY

In bed the other night I turned the reading lamp on to a colour photo of the eastern interior of Gloucester cathedral and just wondered how the soaring walls of glass have stood six centuries of wind and weather. The narrow stone window tracery looks as though it would buckle like blades of grass.

The stone-vaulted roof appears to be supported on walls of glass. The bright windows of the eastern end cant outwards, as Pevsner’s useful guide notes, “creating the impression that it floats unattached to the side walls. The whole space is thus flooded with light.”

It was a revolution in architecture, confirming England in its national style, which, looking back, we call the Perpendicular.

Though a foundation of national standing, Gloucester was not yet a cathedral when the 14th-century Perpendicular rebuilding was done, but the Benedictine abbey church of St Peter.