I bet you have never heard of John Thornton. You may know someone else of that name but the John Thornton I mean was a 15th-century glazier from Coventry in England. Between 1405 and 1408 he worked on his masterpiece, which still stands in situ. It is the Great East Window of York Minster, the largest medieval stained glass window in existence, and one of the finest. Perhaps if it wasn’t part of a cathedral, but had been removed, say, to the Metropolitan Museum of Art in New York, this window, and John Thornton, would be better appreciated for what they are: one of the supreme works of art, and one of the supreme artist-craftsmen, the British Isles have produced.

Cathedrals are the beached whales of our (Christian) culture; undeniably huge and impressive, but washed up, by Matthew Arnold’s ebbing tide of faith, on the shore of unbelief and multiculturalism. They are magnificent but what, now, is their purpose? When I asked a Canadian friend in Barcelona if he felt like visiting the Gothic cathedral, La Seu, he said: “Oh, not another of those old bunkers.” I know what my friend meant but something over the years has kept drawing me back to the great Romanesque and Gothic cathedrals of Europe. Travelling up by train to York the other day, to see the restoration work on the East Front (which leans an alarming 3ft away from true) and the Great East Window, I passed through Peterborough and admired the length of that cathedral with its porticoed, three-arched front. I thought of Ely with its great lantern rising above the fens 15 miles to the east.