English Heritage: The Government's statutory adviser on England's built heritage. Details for visitors of over 400 of the country's most important buildings and monuments, which are in its care

Historic Environment Scotland: Photographs and visitor information on historic buildings and sites open to the public, including castles, cathedrals and monasteries

National Trust: Brief histories and visitor information on over 300 historic buildings and gardens owned by the National Trust in England, Wales and Northern Ireland. Some photographs

National Trust for Scotland: Scotland's leading conservation charity. Details of over 100 properties in its care from castles to cottages, with visitor information