In King John’s reign, castles appeared with larger gatehouses and outer ditches that were deeper and wider. Nearby streams were diverted in order to flood them. The lord’s hall continued to be in the bailey rather than boxed up in a keep, whose importance slowly dwindled. They were built as austere towers, a place of safety in time of need rather than for everyday living; a bolt hole when attacks came. D shaped towers appeared, and were thought to give a better view of enemy activity.
The pic looks east from the motte at Harbottle.