You spend weeks and months on the design – moving from tiny black-and-white sketches to 1:10 half-toned approximations; and then onwards to a full-sized water-colour painting, plus a full-sized black-and-white tonal drawing (to give a clear instruction to us painters about where the light must pass through really clearly) …

And then you finally come to cut the glass, and paint it, and silver-stain it, and also plate it (in order to create the perfect colour as you see it in your mind), then you paint and silver-stain the plating.

At last the piece is encased in lead, with neatly mitred joints to show each graphic angle. Cemented and polished. Fitted in its various frames with steel armatures.

So, tonight, it lies “finished” and strapped against our A-frames, in readiness for tomorrow’s installation, but – exactly because it is an architectural piece – until tomorrow, when we fit it, who knows what this window really is?

That is our responsibility as designers and painters of stained glass. Responsibility to the donor and his memories and his loss. Responsibility to the building itself. And responsibility to the people who will enter the building, each with their own particular memories and their own particular loss.

These unimaginable things matter – nothing else.