I read in the Evening Standard that an exhibition is being held of little pots. Someone went on a tour of the building works at London Bridge station and saw the stuff they were digging out of the ground and ‘I recognised it because I’m a ceramicist’. It was clay! And she couldn’t bear to see it thrown away, it was much too valuable.

So now a ceramicist knows what every labourer, every grave digger, pipe layer, tunneler, surveyor and gardener  has known ever since the first neolithic settlement in the Thames estuary however many thousand years ago.  What everybody who has ever played football in Clissold Park in winter knows. What half of Ireland learnt years ago and half of Poland  now knows, and everybody who has ever gone for a walk on Hampstead Heath when it’s been raining, and all of us who’ve looked hopefully in skips and  seen nothing but massive sticky lumps of yellow-grey clay.

London clay was never much in favour for pottery, but they did make a few billion bricks from it, the characteristic yellow London stocks.   Farmers hate it. In Middlesex (thankyou Wikipedia) they used to speak of ‘ploughing up poison’. And one reason for the much more extensive development of the tube network north of the river is that clay is easy to tunnel through, and in the south it lies too deep.