Like Headstone Manor, Manor Farm in Ruislip is a moated farm, possibly the site of a motte and bailey castle. After that it was a priory and then a farm.
The great barn was built about 1300 AD and is thought to be the oldest existing barn in London. Unlike the one in Harrow, it is an aisled barn. It is 110 feet long and 29 feet wide. The roof has staggered lower purlins braced with raked struts and a pair of upper purlins btaced at intervals with collar beams.
The barn is still part of the Manor Complex which is now the Heritage Centre for the Borough of Hillingdon in London. It hosts events such as the Duck Pond food and crafts market held on the third Sunday of each month and is also available to hire for weddings.
