In Cornhill, opposite the north end of Change Alley. Built as a prison for night walkers by Henry le Waleys in 1283 (Lib. Cust. I. 213). So called because it was built in the form of a Tunne standing on the one ende (S. 189), and Riley says that prisons are said to have had the name of "round house" from the Tun (Mem. p.41, n.).
Broken into by prominent citizens in 1299 (Cal. P.R. Ed. I. 1292-1301, p.408). Can this tumult have had any connection with the King's order, 25 Ed. I., that the clergy were not to be imprisoned there ? (Lib. Cust. I. 213).
In 1297 an ordinance was made that the Tun "Thonellus" recently established was to be abolished and no longer used (Cal. L. Bk. B. p.244). But prisoners were still confined there 1299 (ib. p.86) and 1311 (ib. D. p.277).
There was a well to the west of the prison, but in 1405 the Tun was made a cistern for water brought from Tiborne and was thenceforth called the Conduit upon Cornhill (q.v.) (S. 192).
The well was planked over and a strong prison made of timber called a Cage with a pair of stocks therein was set upon it and on the top of the Cage a Pillory for Bakers, etc. (S. 192).
Enlarged by Robert Drope, 1475 (ib.), when the well was rediscovered and turned into a Pump, the Pillory being set further west (ib. 193).
Brewery called ' les Stulpes" and afterwards " le Swan on the hop" opposite "le Tonne," 1427 (Ct. H.W. II. p.444).
The pump was re-erected 1800.
A Dictionary of London. Henry A Harben. 1918.