The Shire Ditch is, as you may expect, a ditch that runs the length of the Malvern Hills. It is known that it was fortified in AD1287 and used as a boundary between the land of the Red Earl, Gilbert de Clare, and Bishop Cantilupe from Herefordshire Cathedral. It is now thought, however, that the ditch was in existence for a long time before this, possibly as early as the Bronze age. The discovery that the Shire Ditch is so much older than originally thought was made by English Heritage during a survey in 2000. The ditch can be seen from the point level with the Great Malvern Priory all the way to Hollybush Hill which is more than 8km. In some places the ditch has been truncated or removed. Much of this was due to 19th and 20th century quarrying activity, but some was also during the construction of footpaths and bridleways in the Victorian period when the hills were a leisure attraction associated with the water cure.
In the 13th century, the Earl of Gloucester, nicknamed the Red Earl, was granted hunting rights to the East of the Malvern Hills by being made "Lord of the Chase". The Red Earl was a very powerful man, owning estates across England, Ireland and Wales and building Caerphilly Castle. However, this was not enough for him and he started straying over to the West side of the hills which was the territory of the Bishop of Herefordshire. The bishop was extremely unhappy and accused the Red Earl of trespass. A hearing was held at Wynds Point in 1278 and the Bishop threatened to excommunicate anyone who did not agree with him. The Bishop duly won.
After this dispute, the Red Earl complained that his livestock were all moving out of his land and into the Bishops land. To stop this movement of livestock, he fortified Shire Ditch. When it was believed that the Red Earl had first created the ditch, it was said that he positioned it slightly downhill from the hills' summit on his side so that the Bishop's animals would find it easy to jump over to his side but be unable to get back again!
To this day, the spine of the Malvern Hills and the Shire Ditch act as the boundary between Worcestershire and Herefordshire.
In 2006 the historic Environment and Archaeology Service in Worcestershire did a thorough condition assessment of the ditch which can be downloaded here.