Access was kindly arranged by the Wealden cave and mining society.
The Barons' Cave is part of Reigate Castle, which was probably built by the second earl of Surrey, William de Warrenne, soon after 1088.
During the time of Oliver Cromwell, the castle was briefly garrisoned by followers of a Royalist uprising in 1648, and then by parliamentary troops after the insurrection had been put down. There was no fighting at the castle, it was just a convenient camp for the troops. None of the original castle buildings have survived, with the exception of the Barons' Cave.
Nobody knows how exactly old The Barons' Cave is. The oldest reference to it dates from 1586. The cave has a long history as a local curiosity. The earliest account of guided tours found so far dates from 1860, when a lady from a nearby cottage had to be summoned to conduct curious visitors around the cave. Visits continued until the 1970s until In 1991 the Wealden Cave and Mine Society reopened the caves.
There have been many ideas put forward to explain why the cave was dug. It is very unlikely that it was the castle dungeon. The quality of workmanship also rules out the idea that it was just the castle cellar, or a sand mine. The through passage could have been dug as a sally port, which is an escape tunnel to allow the besieged inhabitants to surprise their attackers, or to escape unnoticed. This does not explain why the large side passage was dug.
The effort and skill used to dig The Barons Cave, and the size of its galleries, suggest that it was a special and important feature of the castle. The story which gave rise to the name "Barons Cave" is that the barons met there to draw up the Magna Carta in 1215, before making King John sign it. '
