IMG 6756 - London's Ha-ha! in Kensington Gardens

A ha-ha is often thought to be something found in the grounds of old country houses. Nevertheless, there was one in Central London and it formed the boundary between Hyde Park and Kensington Gardens. This ha-ha is said to be amongst the first built in England. Its sometimes claimed Kensington Gardens is the birthplace of the ha-ha (Matters of Fact in Jane Austen: History, Location, and Celebrity By Janine Barchas 2012.) This is most questionable as Stowe House has an earlier ha-ha from 1714 which was built by Charles Bridgeman.
hydepk33 - London's Ha-ha! in Kensington Gardens
1833 Schmollinger map (From Wikipedia)
Ha-ha’s were so named because they were not apparent from a distance and many unsuspecting walkers would suddenly find themselves at the edge of such devices, and be surprised. Hence the exclaimation ‘ha-ha!’
Mystery surrounds the ha-ha’s exact date of initial construction. It is usually claimed it was authorised by Queen Caroline in the 1730’s and this is the usual accepted convention.
However there are occasional references of the ha-ha’s existence quite a few years earlier and its said it was a design by William Kent (who painted many commissions at Kensington Palace.) It seems Kent clearly didnt like fences or walls as these spolit the look of gardens, so he devised these sunken fences following some influence from both Louis XIV and Louis XV of France.
IMG 6755 - London's Ha-ha! in Kensington Gardens
The course of the ha-ha leading south from the North to the Middle Bastion.
Although Walpole credits Kent with the invention of the ha-ha, historian John Martin Robinson claims a John James published an English version of Parisian naturalist’s Dezallier D’Argenville’s ’Theory and Practice of Gardening’ in 1712. Robinson claims that from this work came “the idea of a sunken fence and helped to popularize the device in England.” (Temples of Delight: Stowe Landscape Gardens” 1990) This book must have caught the attention of Bridgeman who then introduced the concept at Stowe.
It is certainly not known exactly who instigated the Kensington Gardens ha-ha – whether it was either Bridgeman or Kent. It is possible that at some point both agreed a ha-ha was needed and thus it was begun sometime in the 1720’s during King George I’s reign.
The ha-ha formed a demarcation between the public areas to the east and the more private Royal parkland to the west in the vicinity of Kensington Palace. In its most complete state it ran south from Buck Hill Gate to the old western section of Rotten Row – where Mount Gate now is. The boundary continued west from Mount Gate to Palace Gate in the form of a walled slope rather than a ditch. Traces of this can still be seen.
In late April 1727 Charles Bridgeman was given a contract by George I in reference to digging the ha-ha. This indicates it was unfinished and in a state of still continuing construction. George I then left on a trip to Hannover, and died en route at Osnabruck just seven weeks later after issuing this new contract to Bridgeman.
The larger part of the ha-ha, including it’s huge Middle Bastion, was clearly completed under Queen Caroline’s reign.
1814 - London's Ha-ha! in Kensington Gardens
The ha-ha in London: Being a Complete Guide to the British Capital by Pennant*
The ha-ha was not meant to keep people out of Kensington Gardens entirely. On certain days usually Saturdays when the Royals were not resident at the palace, well dressed gentry could stroll through the gardens. Nevertheless, soldiers had to be employed at stations along the ha-ha to “exclude any improper persons” who would occasionally find their way into the gardens. (Gentleman’s Magazine 1821 p603)
The Mount:
mount - London's Ha-ha! in Kensington Gardens
Another feature built by Charles Bridgeman was certainly useful for security purposes. This was known as ‘The Mount’, a substantial hill sited near where the Coalbrookdale gates now stand. It gave good views right across the park and was clearly sited to ensure all parts of the ha-ha could be clearly seen. (This aspect is discussed in part two of this series)
dubourg1814 - London's Ha-ha! in Kensington Gardens
IMG 0807 - London's Ha-ha! in Kensington Gardens
The Serpentine bridge, which formed a later boundary in place of the ha-ha.
The old Serpentine bridge (shown above in an 1814 view) was within Kensington Gardens and formed part of the boundary with Hyde park. The ha-ha simply ended on either side of this bridge. When John Rennie built the new Serpentine bridge in the 1820’s its generous width meant it broached both parks and so a boundary consisted of iron railings, linking both ends of the ha-ha, was placed along the middle of the bridge itself.
During the development of ideas for the Great Exhibition of 1851, a ha-ha in the form of a sunken road was planned in order to control crowds and limit them to the Hyde Park side. These unrealised plans included a tunnel giving pedestrians direct access to the exhibition grounds.
IMG 6800 1024x561 - London's Ha-ha! in Kensington Gardens
Info board on the North, or Buck Hill Bastion of the ha-ha. Click to enlarge.
The ha-ha’s demise began quite early with the demolition of the South Bastion in the 1830’s. The North or Buck’s Hill Bastion followed some time later. This was due to the construction of new roads serving Hyde park for the Great Exhibition. The ditch forming the ha-ha itself was infilled during 1868, leaving in some places a slightly discernible ditch.
Parts of the ha-ha wall could still be seen for several decades after infilling, and some short sections remained visible until the 1930’s at least. The ditch itself remained marked on maps until the mid 1950’s.
Today the line of trees and shallow ditch marking Buck’s Hill bastion to the north of the Serpentine Sackler Gallery mark the the ha-ha’s former course. This ditch was dug to show the approximate location where the old bastion once stood.
IMG 6756 - London's Ha-ha! in Kensington Gardens
Site of the North (Buck’s Hill) Bastion nearer to Lancaster Gate with the 1995 ditch.
In May 1995 excavations established the exact location of the North Bastion in Kensington Gardens. These explorations showed the ha-ha was originally a ditch of sizeable proportions and the brick walls were a later addition. This may well delinate the individual phases of ha-ha development during the George I and Queen Caroline reigns.
IMG 6656 - London's Ha-ha! in Kensington Gardens
Remnants of the Middle Bastion with its brick wall.
Just off the north-east corner of the Sackler Gallery, one can see part of the Middle Bastion. Despite being infilled it wasnt demolished. Visible until 1916, it was filled over until partial resurrection 2004. It provides us with proof that a ha-ha indeed existed in Central London.
*Note: Thomas Pennant (1726-1798) was a prominent Welsh writer and historian. He is said to have popularised the mountains of North Wales, and introduced Snowdonia to the world. His book on London was published post-humously.
Continued in part two – The ‘Inverse Panopticon’ at Kensington Gardens

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Yes! Finally something about construction security
in london.

Mick Cunningham

Hi, this is a fine piece of historical detective work you’ve done here. Think you should send your findings through to the Royal Parks website. What I wanted to share with you is this drawing from Joseph Salway’s plan of the Turnpike road from Hyde Park Corner to Counter’s Bridge, curated online at the British Library’s Kensington Turnpike Trust Drawings: Sheet 9 shows the wall that marked the line between Kesnington Gardens and Hyde Park Corner.
There’s a link to see this in Google Earth on that page, which shows the wall as being roughly where the Albert Memorial is now – and is what I suspect might be the beginning of the HaHa.


Hi Mick thanks for the feedback!
I referred my article to Kensington Palace when I first did it and the person whom I emailed made a note of it, nothing more was said after that.
I have seen the Turnpike Road maps previously, however the link you gave me seems to show the next bit along (eg the section east of the Coalbrookdale Gates) hence its difficult to see how this matches the section by the Albert Hall. Unless the mapping people who placed the images on Google havent done it correctly?
I tried to find the right section however I think there must be a number of sections that are not on display (for example Knightsbridge showing Hyde Park Sheets 1-4 etc and the Kensington Gore set are not available) Kensington Gore Sheet 7 ( ) shows the section by the Albert Memorial but it is too far away from the ha-ha to show it.
It would be interesting to see a map that actually shows the ha-ha west of the memorial – I dont think it existed there was possibly a wall instead – if one looks at the lie of the land where the South Flower Walk is I am uncertain there was a ha-ha along this section – therefore the ha ha ended somewhere near about where the Albert Memorial is.