In the later decades of the twentieth century the viaduct had fallen into an ever-worsening condition, with much serious erosion and loss of facings; the western arch had sagged and the second arch had hogged; cracks up to 60 mm had opened up in the extrados of the arch rings. It had become obvious that the structure was near to collapse, and in February 1992 the Laigh Milton Viaduct Conservation Project was formed. It is described below.
