Fonthill Abbey was the stuff of legend in its day and much admired by the great romantic painters Constable and Turner. Walled and girdled round and closed to visitors, it intrigued the regency public; so much so that when it was first put up for sale through Christie’s in 1822, between 600 and 700 people a day traipsed through its soaring mock-medieval halls, gawping up to the plaster vaulting at the top of its wobbly tower. In all, at least 7,200 people paid a guinea each for a catalogue that gave admission to the abbey. It was the Disneyland of its day.