Headstone Manor and Museum

The Survival of Moated Manor Houses in the UK

There is no exact national total for how many water-filled moated manor houses survive in the UK, as heritage agencies track archaeological moat sites rather than water retention. However, archaeologists have identified around 6,000 known medieval moated sites across England alone, many of which still retain water or feature surviving manor houses.

Rare Survival in London

London contains very few surviving historic moated manor houses. Valence House Museum is the only surviving medieval manor house in Dagenham, and it remains partially surrounded by a moat set within Valence Park.

Another notable site is the King Edward III Moated Manor House, a designated Scheduled Monument built between 1349 and 1356 as a medieval moated manor house and royal residence. Today, it survives largely as buried and upstanding ruined walls rather than an intact house.

Headstone Manor

Headstone Manor is a remarkably preserved historic site located in the London Borough of Harrow. Centred around a Grade I listed moated manor house, it is widely recognised as London's only fully surviving water-filled moated manor house and the earliest surviving timber-framed building in the historic county of Middlesex. Together, the site spans over 700 years of English history.

Origins and the Medieval Period (14th Century)

Documentary evidence shows that there was a house on this site from 1233, with the footprint of this building marked on the site by a brick outline. No one knows if there is any older material on site.

The core of Headstone Manor was built around 1310 during the reign of King Edward II. For its first few centuries, the estate was not in private hands, but was instead owned by the powerful Archbishops of Canterbury.

The Archbishops used the manor as an administrative centre and country retreat for managing their vast agricultural estates in the area. Structurally, the original building was a classic medieval moated complex featuring a timber-framed hall designed to showcase ecclesiastical power and wealth. The surrounding water-filled moat served both as a status symbol and a defensive barrier.

The Reformation and Secular Ownership (16th–18th Centuries)

In 1546, during the English Reformation, the estate was surrendered by the Church to King Henry VIII. This marked the end of the Archbishop’s tenure and the beginning of a long line of secular, private owners and tenant farmers.

Over the succeeding centuries, successive occupants altered and expanded the buildings to suit changing architectural fashions and domestic needs:

• The 17th Century: Substantial additions were made, including wood-panelling in the Great Hall (dating around 1631) and the introduction of interior brick chimney stacks to replace open hearths.

• The 18th Century: The exterior underwent significant modification, including the addition of a Georgian-style brick façade to the front of the building around the 1770s, masking much of the medieval timber work from the outside.

The Wider Historic Estate

In addition to the main manor house, the Scheduled Monument site includes three other vital historic agricultural buildings that reflect its long farming history:

• The Great Barn (Grade II* listed): A magnificent timber-framed barn used historically for storing grain and crops. Headstone Manor was a working farm, and consequently was surrounded by many ancient farm buildings. By the early 20th century, the majority of these buildings had fallen into a state of disrepair and were eventually destroyed. Only two remain, and by far the most impressive is the farm building now known as the Great Barn, formerly referred to as the Tithe Barn.

  Built in 1506 on the orders of the then Archbishop of Canterbury, the Grade II* listed Great Barn has a framework made entirely from English Oak, measuring an impressive 43 metres (141 feet) long and nine metres high. Originally, the Barn would have been mainly used by the tenant farmer of Headstone to store grains and stable horses, with a few bays reserved for the use of the Archbishop. 

  By the 1920s, the Barn was in a very poor condition. It was not until a major restoration project carried out by the London Borough of Harrow in the 1970s that the Great Barn was bought back to its former state of glory. The Great Barn was converted to provide the facilities needed for an active museum. The resulting rich brown weather-boarded building with ancient tiled roof formed the first usable building of Harrow Museum when it opened in 1986.

• The Small Barn (Grade II listed): Now transformed into the modern visitor entrance. Excavations at the site of the Small Barn have revealed fragments of prehistoric and Roman pottery, indicating that the site of what is now Harrow Museum was inhabited thousands of years ago. Archaeological excavation has also shown that the foundations of the Small Barn date back to the 14th century, making it contemporary with the first phases of the building of Headstone Manor house and the moat.

  The Small Barn stands opposite the giant Great Barn, and originally would have been two buildings standing end to end. Re-roofed as one with a drainage channel through the middle, it is likely to have been used to house livestock. It is thought that a series of structures have stood on the site, though most of the wood today appears to be from the same period as the early 16th century Great Barn.

  In the mid-1970s, the Small Barn was almost destroyed by a fire. After 20 years of being covered by a protective plastic canopy, the burnt out skeleton of the building was finally restored. The Small Barn is a Grade II listed building and re-opened in autumn 2017, with archaeological exhibitions and a film.

• The Granary (Grade II listed): Previously used for grain storage, now serving educational and community facilities. The Grade II listed Granary is the only museum structure that was not originally built as one of the farm buildings of Headstone Manor, having been originally constructed about a mile away in Pinner Park Farm. After becoming redundant and falling into a dilapidated condition it was carefully restored, before being moved to the Harrow Museum site in 1991.

  Dating from the late 18th century, the Granary was actually a cattle feed store. Although it only has a ground floor and a first floor, the building has an extraordinary number of windows to the upper stories, making it a rather puzzling building. Originally the building would have been longer, but one end stood in damp ground and rotted away, reducing the Granary to its present size.

  The Granary building fits well into the context of the Harrow Museum site. It was opened to the public in 1992, and re-opened as a learning space after Heritage Lottery Fund restoration works in autumn 2017.

Evolution into a Museum

By the 20th century, the agricultural land surrounding the manor was largely developed into suburban housing for Harrow, but the core estate survived. In 1986, Headstone Manor officially opened as Harrow Museum, run largely by volunteers and local enthusiasts to preserve the heritage of the borough.

Following a major multi-million-pound restoration project supported by the National Heritage Lottery Fund, the site underwent extensive conservation. This allowed the medieval manor house to reopen fully to the public, presenting its rich, layered architectural history, from 14th-century timbers to Georgian brickwork, as the primary exhibit itself. 

Today, the site also houses the extensive Harrow Local History Archive.

The Moat Café and Visitor Centre

Located near The Small Barn, The Moat Café and Visitor Centre is where freshly ground coffee, cakes, paninis and other hot snacks are available. The Visitor Centre also houses a gift shop, with a range of handcrafted pieces including jewellery, books and children's gifts. The Visitor Centre also contains a disabled toilet and baby changing facilities. The Moat café and visitor centre is open every day except Mondays.

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Key Facts on Moated Sites and Manor Houses

National Distribution and Water Retention

Roughly 6,000 medieval moated sites are recorded across England alone, encompassing a variety of structures such as farmsteads, monastic granges, and elevated manor platforms. However, not every moated site holds water today. Over the centuries, many moats have dried out, silted up, or naturally transitioned into shallow earthwork ditches and dry depressions.

Notable Surviving Examples Across England

Beyond London, several exceptional country houses showcase intact medieval architecture paired with operational water moats. Baddesley Clinton in Warwickshire is a renowned medieval moated manor house completely surrounded by an active water moat. Similarly, Helmingham Hall in Suffolk is a historic moated manor featuring a wide, water-filled double moat that remains a striking visual landmark.

In Kent, Ightham Mote stands as a magnificent fourteenth-century moated medieval manor house complete with an entirely intact water-filled moat. Further north, Markenfield Hall in North Yorkshire offers a remarkably complete early fourteenth-century moated manor house experience, preserving much of its medieval defensive and domestic character.