The Great Barn at Harmondsworth: 600 years of grandeur, history and restoration, now under threat by Heathrow’s third runway

The Great Barn at Harmondsworth is the largest standing medieval timber-framed structure in Britain – and it has just been restored. Edward Impey investigates the remarkable story of its construction and its medieval use. Photographs by Will Pryce.

The Great Barn at Harmondsworth, built by Winchester College in 1425–27, is arguably one of England’s most important medieval buildings. It may lack the artistic and ostentatious appeal of castles, houses and churches, yet it served a more essential and immediate purpose: the ceaseless round of the farming year on which the existence of both great and poor depended.

At more than 192ft long and 37ft 6in wide, it is one of the largest barns known to have been built in medieval England and one of a distinct group of about 20, termed Great Barns, that are head and shoulders above the rest and all built by monasteries or institutions.

Many, such as Reading Abbey’s barn at Cholsey, Berkshire (now Oxfordshire) or that of Peterborough Abbey are wholly lost; others such as the gigantic building at Abbotsbury, Dorset, or Beaulieu Abbey’s home farm barn at St Leonard’s, Hampshire, are all or partly ruined.

One of two tithe barns in Peterborough undergoing demolition. Photograph first used in Country Life magazine on 6 May 1899. The barn was in good repair, but was pulled down by the Church Commissioners to create land for development. Photo: Country Life Picture Library

One of two tithe barns in Peterborough undergoing demolition. Photograph first used in Country Life magazine on 6 May 1899. The barn was in good repair, but was pulled down by the Church Commissioners to create land for development. Photo: Country Life Picture Library

Harmondsworth also has the distinction of being the largest timber-framed free-standing medieval building in the country.

Scale and a few oddities apart, the design of the Great Barn followed a pattern that was well established: a high central ‘nave’ is flanked with lower aisles to each side

The vast expanses of the main roof slopes, clay-tile covered in the 1420s, sweep down to 7ft from the ground and the ends are half-hipped, finished with ingeniously constructed gablets.

The walls were clad in broad upright boards, all laboriously hand-sawn. Most of them survive and rest on low sill walls of mixed stonework. The aisle posts – the main uprights, hewn out of whole oaks, which form the longitudinal nave arcades – stand on massive blocks of green sandstone from Reigate in Surrey.

Nowadays, although tidied up and with the farm smells of grain, beets, straw, manure and old diesel long gone, the barn’s pristine emptiness means that the functional combination of its towering verticals and curved braces can be readily appreciated.

Not surprisingly, then, although it is celebrated as a feat of engineering and beloved of carpentry historians, the Great Barn has had its admirers as a piece of architecture, the most famous being Sir John Betjeman, who was taken there by Simon Jenkins in 1973. He followed in the wake of a litany of Gothic Revival and Arts-and-Crafts designers: George Gilbert Scott made sketches there in 1847 and was later prompted – years before William Morris’s famous words on Great Coxwell – to praise medieval barns in general ‘as good and true in their architecture as cathedrals’. He also based an earthquake-resistant scheme (sadly unbuilt) for Christchurch cathedral, New Zealand, on it.

14434-11 Villages of London Airport - The Tithe Barn at Harmondsworth. Photograph: Jonathan M Gibson/Country Life Picture Library, published in 28/09/1972. Even back then the idea of a third runway at Heathrow was mentioned as a possible threat.

The Tithe Barn at Harmondsworth. Photograph: Jonathan M Gibson/Country Life Picture Library, published in 28/09/1972. Even back then the idea of a third runway at Heathrow was mentioned as a possible threat.

George Edmund Street went there, too, probably with Scott. Basil Champneys based much of the library of Mansfield College, Oxford, on what he saw. Ernest Gimson, who went there in 1880 with William Richard Lethaby, did much the same in his massively timbered Memorial Library of 1921 at Bedales School, Hampshire.

Medieval documents, mostly in the Winchester College archives, tell us how the Great Barn was built, how it was used and of the people involved. The first mention in the accounts is a payment made in the 12 months up to September 1425 to a certain John att Oke and one William Kyppyng for inspecting standing timber ‘for the barn at Harmondsworth’. The last we hear of its construction is that tiling the roof was complete by September 1427.

In case of any doubt, tree-ring dating has confirmed that the barn’s main timbers were felled in the winter of 1424–25 and the spring of 1426, suggesting that the frame was prefabricated during 1426 and erected, still green, during the spring and summer of 1427. The roof tiles were made at Harmondsworth and the ‘ferricrete’, a natural iron oxide-cemented gravel, used in the sill walls, quarried nearby.

The main timber joints were pegged, but tens of thousands of nails were also needed, together with other ironwork, and this came from further afield. Among it were the door hinges picturesquely described as ‘gosefett’ (presumably of the three-strap variety) and ‘woodcobbeleez’ – probably ‘woodcock bills’ and, if so, with a single straight strap.

The Great Barn at Harmondsworth ©Will Pryce/Country Life Picture Library

Among the men involved were the smith John Derfford, who made the hinges, and Robert Helyer the master tiler, who received a massive £1 bonus in 1427 ‘over and above the contracted price for the roofing of the said barn’. The overall cost was about £90, roughly 18 months’ worth of the manor’s profits. The carpenters and tilers were paid 4d per day, about twice an agricultural wage.

As for its purpose, the Great Barn (and other great barns) was not a tithe barn. Such buildings, for storing a 10th part of the produce of the parish, were usually modest constructions and rarely survive. The Great Barn was for the storage of the cereal crop from the college’s demesne – that is, the in-hand land of the manor – about 240 acres of which was sown annually in the 1420s.

The crops in question were wheat, barley and oats – in that order – as well as peas and beans ‘in the stalk’. All these could be kept in ricks, but risked being spoiled when the rick was opened and, in an age when grain was nearly as negotiable as coin, barn storage kept it under lock and key.

Management of the estate was ultimately down to the fellows of the college and the warden – at this time, Walter Thurburn – but was largely delegated to a steward, aided by clerks and the two fellows appointed annually as bursars.

At Harmondsworth itself, the senior local official was the bailiff – in the 1420s, the long-serving Roger Hubbard – to whom others reported, some permanent, some seasonal. He and his wife seem to have been favourites with the college, which, on two occasions, presented Mrs Hubbard with lengths of coloured cloth.

The endless round of ploughing, harrowing and then sowing and weeding the crop was carried out by ‘customary’ tenants, whose rent was paid through fixed annual services, and by hired labourers. The high point of the year was, as ever, the harvest: reaping the standing corn, binding it into sheaves, stooking them, and then, once they were dried by sun and wind, carting them to the barn. There, they were counted and recorded, with the aid of tally sticks, and then stacked, a skilful and arduous business supervised by the barnkeeper or granger.

14434-11 Villages of London Airport - The Tithe Barn at Harmondsworth. Photograph: Jonathan M Gibson/Country Life Picture Library, published in 28/09/1972. Even back then the idea of a third runway at Heathrow was mentioned as a possible threat.

The Tithe Barn at Harmondsworth in 1972, then still in regular use. Even back then the idea of a third runway at Heathrow was mentioned as a possible threat. Photograph: Jonathan M Gibson/Country Life Picture Library, published in 28/09/1972. 

With the harvest in, a feast was held in the hall of the manor house – numerous ‘reap-geese’ are mentioned in the accounts, together with staggering quantities of ale; for the working man, these occasions must have been as merry as medieval England got.

Over the months that followed came the threshing, a longer, harder and more expensive task than the harvest itself. Teams of men and women with jointed flails beat the sheaves laid out on the ground, periodically raking away the stalks, shovelling the debris into the air and fanning it to separate the grain from the chaff. Sums spent on a number of such fans are noted in the medieval accounts.

Once safely stowed in the granary, the grain was issued, some for consumption on site or as a form of payment, but mostly for sale on the voracious London market, the wheat for bread and the barley largely to brewers.

Peaceful as all this sounds, the relationship between the college and its tenants was rarely tranquil. At a time when most landlords were commuting customary works for cash, the college insisted that its tenants did the work. The result was a series of strikes and, in 1450, what amounted to a tenants’ revolt, perhaps emboldened that summer by news of Jack Cade’s rebellion in Kent. All this cost the college a lot of money, as the scribe carefully put it, because ‘the customary tenants were unwilling to carry out their customary duties that year’.

The Great Barn at Harmondsworth ©Will Pryce/Country Life Picture Library

The Great Barn at Harmondsworth ©Will Pryce/Country Life Picture Library

Winchester’s ownership ended in 1543 when, no doubt with some reluctance on the part of the college, Harmondsworth was ceded to Henry VIII in exchange for other properties, which were mostly formerly monastic. Edward VI, however, soon sold it to Sir William Paget, a royal official ennobled in 1549, whose descendants – from 1714, the Earls of Uxbridge – held it until 1774.

It was bought in that year by the Cotton family (later Powell-Cotton) of Quex Park, Kent, and the barn was then frequently shared by a number of tenants. The estate was eventually broken up and sold after the Second World War, but farming use continued until the 1970s. When this ended, however, the Great Barn joined the ranks of thousands of historic farm buildings unsuited to modern machinery or shorn of the working farm they served and with no obvious or economic function.

Things came to a head in 2009, by when English Heritage – which, through its statutory arm (now Historic England), had been involved for years – was the only body that could save it. In short, in 2011, the barn was bought for a token sum and then, in 2014–15, was subject to a meticulous two-year conservation and re-roofing programme, at a cost of more than £570,000.

Now, with the support of the Friends of the Great Barn at Harmondsworth, it is open, at no charge, on half the Sundays in the summer. However, with one battle won, another looms with the threat of Heathrow’s possible expansion: having grown since its beginnings in 1930 as the Fairey Aviation Company’s Great West Aerodrome (renamed after a row of cottages on the edge of Hounslow Heath), the airport is now the seventh busiest in the world. More to the point, as recommended by the 2015 Davies Commission, the vexed third runway would lie no more than 500ft away, leaving the building standing, but in utterly degraded surroundings and bereft of its village community.

Would this be the best response? Or, in the face of all sound conservation orthodoxy, should the Great Barn be uprooted and rebuilt in exile? The debate will not be dull, but, either way, the Great Barn will continue to impress, to encourage the appreciation of such magnificent buildings and connect us today with the essential aspects of our history they represent.

The Great Barn at Harmondsworth is open on the second and fourth Sundays, April to October. Visit www.english-heritage.org.uk/harmondsworth-barn. Edward Impey’s book ‘The Great Barn of 1425–27 at Harmondsworth, Middlesex’, written with Daniel Miles and Richard Lea, is published by Historic England.