And in full sight, next to the Jewel Tower, is another of London’s significant medieval structures, though this time while ‘just’ a wall, it’s the magnificent ancient precinct wall of Westminster Abbey[1]. The wall separates College Garden from Abingdon Green and around the corner up Great College Street, including 5 medieval gates. The lower sections used to be waterfront when the Thames was much wider. It’s called either the Westminster Abbey Precinct Wall or the College Garden Wall.

As Tim Tatton-Brown explains, that while generally it “ … uses only [Kentish] ragstone rubble… immediately to the south of the Jewel Tower moat, one can see a small area of the lowest section of the Abbey’s boundary wall at the bottom of the ramp leading down into the 1960s Abingdon Street underground carpark… This section of the wall, which is slightly battered (sloping), is also made with high quality ashlar masonry, as it, too, was originally built on the Thames foreshore” [2]

These much larger stones can be seen clearly in the intro to The Prisoner! [3] and in this photo of the ramp into the carpark. This also illustrates how much the land surface has risen up over the centuries.

The long section along what is now Abingdon Green and above the ramp down into Abingdon Street Car Park is older than the section cutting past the Jewel Tower, which is of the same date as the tower.

The Historic England listing states “Precinct wall. Early medieval and c.1374 with later additions and alterations. 20 ft high wall of Kentish Ragstone rubble with ashlar below high tide level along the former river front, weathered brick coping. The wall can be traced above ground level eastwards from the left hand part of the ground floor of No. 30 Great College Street, free standing along the south and east sides of the Abbey or Canons’ Garden. The re-entrant opposite the Jewel Tower was built c.1374-76 and is incorporated into No. 4 and the otherwise post war rebuilt No. 3 Little Cloisters. The early wall returns westwards to the south of the Chapter House and is incorporated into the back north elevation of Nos. 2, 2A, 2B and No. 3 Little Cloisters with rebuilt octagonal stone tower to rear of No. 1. To Great College Street there are late medieval 5-centred arched doorways and later C.18 and C.19 square headed doorways inserted.” [4]

Presumably if the whole area were to be excavated the lower ashlar courses would be found throughout. Is any visible in the underground garage or have they been completely hidden behind concrete wall.

While the wall is mainly of Kentish Ragstone, and that is what London Pavement Geology has it as [5], flints and bits of old tile can be seen too and the gates are of a softer stone, maybe Reigate or Caen.

The date of all of the wall it is unclear. In 1924 in the Inventory of Historic Monuments it was said of the wall that it is  “… of ragstone-rubble and was probably built in the 14th century…” [6] and clearly the section of wall around the Jewel Tower is of that date, as after all that original section of wall was demolished to build the Jewel Tower. But it is unclear how much of the wall dates back to the establishment of the garden on the other side. Is some of the wall 11thC?

The Historic England listing states “Early medieval and c.1374” so that is the assumption. [4] though ‘early medieval’ refers to up to the 10thC and it’s not clear if the wall is that old as the site at Westminster only began to be developed in the mid-11thC [1] and properly in the 12thC.

HJM Green identified 3 phases of building, an early river wall, lower courses then later building, in his 1963 excavations when the underground car park was being built. He states “The phase 2 stretch of the Abbey precinct wall was probably contemporary with the construction of an ashlar faced waterfront wall, into which it was bonded. This 6ft wide wall was of similar build to the precinct wall and survived to a height of 12ft at its west end ... It has been traced for I30 ft eastwards towards the present river line and may have formed part of the riverside quay and wall built around the palace during the minority of Henry III (between 1216 and 1227). If so, then the phase 2 Abbey precinct wall is also of this date.” [7]

And refering to the section by The Jewel Tower “The erection of the Jewel Tower in I365 involved an encroachment on the land of Westminster Abbey … Part of the old precinct wall was demolished and a new wall (phase 3) was built some 40ft further to th e west by Abbot Litlyngton c. I374-6.”

This seems to clearly date the main stretches of the wall to the early 13thC, and the section around The Jewel Tower to 1374-6.

A summary in Medieval Britain in 1964 stated “At least three building periods can be distinguished along the line of the precinct wall. During the earliest a corner tower was built at the S. end of the wall near Great College Street. The return face of the tower was faced with squared Kentish rag rubble, whose lower courses were bonded into an earlier river wall below the existing precinct wall….The main stretch of the E. precinct wall of the Jewel Tower belongs to the second period. Its upper part is of coursed rubble, but below the medieval high-tide level the structure had a battered ashlar face supported on an oak wall-plate and elm piles … This stretch of the precinct wall was contemporary with, or perhaps slightly earlier than, the ashlar-faced quay which was bonded into the precinct wall, was of a similar build to it and still survived to a height of 12 feet. The precinct wall of period 2 continued N. under what is now the Jewel Tower, and its foundations were found when no. 5 Old Palace Yard was demolished.

The stratigraphical evidence indicates that the quay, and thus also the precinct wall of period 2, are earlier than the Jewel Tower and its moat built in 1365-6. On the side of the moat the foundation trench of the palace curtain wall cut through a rubbish pit containing iron-working debris and pottery (including baluster jugs, one of which was decorated with scallop shells and stars) of c. 1280- 1300. Some time after 1365-6 the curtain wall on the N. side of the moat was rebuilt or refaced from about I t ft. above the early medieval ground level upwards. The refacing on the N. side is of knapped flintwork with galleting and is associated with the construction of a flight of steps leading down to a wooden landing stage (PL. XXIII, B). On the N. side of the moat and running parallel with the curtain wall was an inner line of medieval defences belonging to the palace. The 5-ft.-wide curtain wall was built of reused materials, and at its W. end formed part of a massive structure with walls over 8 ft. in width, which may have been a tower at the SW. corner of the palace defences, possibly earlier than the Jewel Tower.

The erection of the Jewel Tower involved an encroachment into the land of the abbot and convent of St. Peter’s, Westminster. Part of the old precinct wall was demolished and a new wall (period 3) was built some 40 ft. farther W. by Abbot Litlyngton c. 1374-6. At its junction with the earlier wall, the new one was preserved to its full height and had a pointed stone capping. Both walls had doorways, fireplaces and ovens inserted into them which had formed parts of buildings constructed against them in post-medieval times.” [8]

The original walls may well be 12thC “By 1180, the Abbey precinct had been enclosed by boundary walls and a ditch.” [9]

The other side of the wall is College Garden, [10] from which the other side of this medieval wall can be seen. [11] Nb Abingdon Green [12] is often wrongly called, regarding it’s use for TV broadcasting re events in Parliament, College Green.

Visting
The outside of the wall can be seen at any time, but visiting the inside via College Garden is more complicated. The garden is normally open in the week, but not week/ends, from 10-4 but it is also sometimes closed for functions so phone before you go.
https://www.westminster-abbey.org/about-the-abbey/contact-us

References
[1] https://en.wikipedia.org/wiki/Westminster_Abbey
[2] ‘Kentish ragstone ashlar masonry in London’ Autumn 2016 London Archaeologist 261 https://archaeologydataservice.ac.uk/archiveDS/archiveDownload?t=arch-457-1/dissemination/pdf/vol14/vol14_10/LonArch_14-10_5_tatton-brown.pdf
[3] https://www.youtube.com/watch?v=M3LT98uOwck&ab_channel=TheRealSarcasticus
[4] ‘Abbey precinct wall’ https://historicengland.org.uk/listing/the-list/list-entry/1357235
[5] http://www.londonpavementgeology.co.uk/location-details/?id=3147&zoom=17&lat=51.497682&lon=%20-0.127150
[6] ‘Inventory of Monuments of Westminster Abbey: The Monastic and Collegiate Buildings’, in An Inventory of the Historical Monuments in London, Volume 1, Westminster Abbey (London, 1924), pp. 76-93. British History Online http://www.british-history.ac.uk/rchme/london/vol1/pp76-93  
[7] https://www.tandfonline.com/doi/abs/10.1080/00681288.1976.11894975 [ Paywall ]
[8] https://archaeologydataservice.ac.uk/archiveDS/archiveDownload?t=arch-769-1/dissemination/pdf/vol09/9_170_220_medieval_britain.pdf
[9] https://www.westminster.gov.uk/sites/default/files/13.6_13_07747_full-historic_environment_assessment-3128778.pdf
[10] https://en.wikipedia.org/wiki/College_Garden
[11] https://thethorneyislandsociety.org.uk/ttis/index.php/thorney-tales/75-thorney-tales-11-the-abbey-garden
[12] https://www.ianvisits.co.uk/articles/londons-pocket-parks-abingdon-green-sw1-56131/