History of Harmondsworth Barn

The barn at Harmondsworth was built in 1425–7 on land bought by William of Wykeham, Bishop of Winchester, in 1391, to endow Winchester College. Used mainly to store cereal crops before threshing, it remained in agricultural use until the 1970s. At 58 metres (192 ft) long and 11.4 metres (37 ft 6 in) wide, the barn is one of the largest ever known to have been built in the British Isles, and the largest intact medieval timber-framed barn in England. It was bought by English Heritage in 2011.

Harmondsworth Barn from the south-east with red roof tiles catching the sun and a dramatic sky above
Harmondsworth Barn from the south-east

The Priory of Harmondsworth, 1069–1391

As a property of Harold II, King of the English, the manor of Harmondsworth passed to William I at the Norman Conquest. In 1069 the new king granted it to the abbey of La Sainte-Trinité du Mont, just outside Rouen in Normandy.[1] The abbey was one of many continental monasteries to be enriched with English property after 1066.[2]

At least by the early 13th century, a monk with the title of ‘Prior’ was stationed at Harmondsworth to manage the estate and send its revenues to France. By the 1260s (as probably from the start), he was accompanied by another monk.[3]

Their house was designed along entirely secular lines: an inventory of 1324 implies the existence of a hall, chamber, kitchen and service room, and lists the usual domestic equipment including their two beds.[4] Relations between the monks and their tenantry were far from smooth and sometimes violent, disputes over rights leading on various occasions to an assault on the prior in his chamber, the destruction of documents, arson and murder.[5]

By the late 14th century war with France had long hindered the abbey’s access to its English income. In 1391 the manor of Harmondsworth was sold to William of Wykeham, Bishop of Winchester (d.1404), who was then accumulating an endowment for his newly founded college at Winchester.[6]

A bailiff was installed in the prior’s house to manage the estate, and the house and farm buildings inherited from the monks, including a ‘corn barn’ and a ‘great barn’, were repaired.[7]

Engraving of the barn in the mid-19th century showing it filled with straw or hay
The barn in use in the mid-19th century (from E Walford, Greater London: A Narrative of Its History, Its People, and Its Places, vol 1, London, 1883, p 204)

The Property of Winchester, 1391–1543

As Winchester accumulated properties during Wykeham’s lifetime, the College systematically repaired or rebuilt the houses and farm buildings that went with them. At Harmondsworth the old ‘great barn’ was kept until it was replaced by the existing structure in the 1420s.

The first reference to a new barn in the College accounts shows that in the 12 months from Michaelmas (29 September) 1424 to Michaelmas 1425, John att Oke and William Kyppyng inspected some timber near Kingston upon Thames ‘for the barn at Harmondsworth’.[8]

The accounts for the following year show that the ‘newly built’ structure was finished and roofed by September 1427.[9] Dendrochronological (tree-ring) dating of the existing barn shows that its timbers were felled in the spring of 1426, and that it is therefore the one mentioned in the accounts, and was built from scratch within the space of about 15 months.[10]

The cost of building the barn remains to be firmly identified, but was in the region of £50–£100. Neither Kyppyng’s nor Oke’s role in the barn’s construction is completely clear: Oke is otherwise unknown, and Kyppyng’s only other known building work (destroyed) was at Downton church in Wiltshire. His pay-rate, however, suggests a junior rather than a master carpenter: someone else, as yet unidentified, may have been the actual designer.[11]

The main purpose of the barn was to house the wheat, barley and oats produced on the estate, stored ‘in the ear’ (ie in the form of sheaves). This was then threshed (separating the grain from the stalk) as required, probably on the ground just inside the doorways.

The processes of carting the sheaves to the barn, counting them, stacking them, estimating how much grain the year’s harvest would yield, and issuing the threshed grain to the official in charge of the granary where it was stored, are all well known, in general terms, from medieval treatises.[12] Documents relating specifically to Harmondsworth (both before and after Wykeham’s purchase) reveal arrangements along standard lines.[13]

The size of the barn at Harmondsworth seems to have been carefully based on the average yield of the home farm, as its usable internal volume of about 3,310 cubic metres matches the 2,800 cubic metres which, at a rough estimate, would have been needed to store the produce of its 236 acres (96ha).[14]

The barn’s contents were not, as often supposed, received in tithes – the tenth part of the manor's agricultural produce to which the College, as corporate rector, was entitled. There was a tithe barn at Harmondsworth, but it was a very much smaller building and had disappeared by the 18th century.

Black and white photograph of Harmondsworth Barn as a working farm building in 1974
A photograph of the barn taken in 1974, during its last years as a working farm building. The lean-to and additions of various dates were all removed in the 1980s © London Metropolitan Archives

Later History

In 1543 the property was exchanged with another at Henry VIII’s command.[15] Four years later it was sold to the Paget family (later Earls of Uxbridge and Marquesses of Anglesey), who kept it until 1774.[16] A series of detailed leases from the 1580s onwards records the names of the tenants and their rights and shows that Harmondsworth remained a productive estate, although subdivided into a number of separate farms.[17]

The largest of them, Court Lodge, included the medieval buildings, although the tenant had no need for the whole barn and by 1687 was only leasing two bays within it.[18]

Thereafter, the farm, barn and other buildings remained in agricultural use until the 1970s, the last active farmer being WG Potter.[19] The barn’s best-known admirer in this period was no less than Sir John Betjeman (1906–84), who likened it to a cathedral.[20]

Once out of agricultural use, the barn continued to be used for storage and was generally well maintained. Its future became uncertain, however, after it was bought as a speculative investment by an offshore company in 2006.

With virtually no maintenance being carried out, the condition of the barn began to deteriorate, and it was left to English Heritage to carry out urgent repairs. By 2011 the only means of securing its future was purchase by English Heritage, and it is now part of the National Collection and regularly opened to the public.

About the Author

Edward Impey is a specialist on aspects of medieval architecture and history, former Director of Heritage Protection and Planning at English Heritage and now Master of the Royal Armouries. Michael Dunn is Principal Inspector of Historic Buildings and Areas for Historic England. 


1. JF Pommeraye, ‘Histoire de l’Abbaye de La Sainte Trinité-du-Mont de Rouen’, in Histoire de l'Abbaye de La Sainte Trinité-du-Mont, dite depuis de Sainte Catherine du Mont de Rouen (Rouen, 1662); A Deville, ‘Cartulaire de l’Abbaye de la Sainte-Trinité du Mont de Rouen’, appendix to BCE Guérard, Cartulaire de l’Abbaye de Saint-Bertin (Paris, 1840), 455.
2. D Matthew, The Norman Monasteries and Their English Possessions (Oxford, 1962); E Impey, ‘The alien priory of St Winwaloe and Winnold House at Wereham, Norfolk’, Norfolk Archaeology, 44 (2004), 432–54.
3. T Bonnin (ed), Regestrum Visitationum Archiepiscopi Rothomagensis (Rouen, 1852), 530.
4. The National Archives (TNA), E 106/7/18 no. 8 (extent of Harmondsworth manor, 1324).
5. E Impey and D Miles, ‘The great barn at Harmondsworth, Middlesex’, English Heritage Historical Review (in preparation).
6. V Davis, William Wykeham: A Life (London, 2007), 121–2; A Shipp, ‘William of Wykeham and the founding of Winchester College’, unpublished PhD thesis, University of Exeter (2008), 185–90.
7. Winchester College Muniments (WCM) 11502.
8. WCM 22103 (account of Robert Heate and Richard Boureman, bursars of Winchester College, 29 September 3 Henry VI [1424] – 29 September Henry VI [1425]).
9. WCM 22104 (account of William Wyke and Richard Boureman, bursars of Winchester College, 29 September 5 Henry VI [1426] – 29 September 6 Henry VI [1427]).
10. I Tyers and H Hibberd, ‘Tree-ring dates from the Museum of London Archaeology Service: list 53’, Vernacular Architecture, 24 (1993), 50–54.
11. Impey and Miles, op cit.
12. For example, the late 13th century Husbandry by Walter of Henley (ed D Oschinsky, Oxford, 1971), 309–43.
13. Including TNA, SC 12/11/20 and SC 11/444.
14. Impey and Miles, op cit.
15. G Wyld, ‘Harmondsworth manors and other estates’, in Victoria County History: Middlesex, vol 4, ed JS Baker and TFT Cockburn (London, 1971), 7–10; Letters and Papers, Foreign and Domestic, of the Reign of Henry VIII, vol 18 pt 2 (London), 124.
16. D and S Lysons, An Historical Account of those Parishes in the County of Middlesex which are not included in the Environs of London (London, 1800), 139.
17. London Metropolitan Archives, Acc0446/EM/040.
18. London Metropolitan Archives, Acc0446/ED/162.
19.  Justine Bayley, pers. comm.
20. Simon Jenkins, ‘John Betjeman’s Heathrow’, in The Selling of Mary Davies and Other Writings (London, 1993), 63–70; Candida Lycett Green, pers. comm.

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