What is left of a very large heath
Hounslow Heath is about two hundred acres of long grass, heather, scrub and young woodland, run by the borough as a local nature reserve and hemmed in by ordinary roads: the Staines Road along the top, the Hanworth Road down one side and the River Crane along the far edge. It sits in TW4, a steady walk or a short bus ride south of Hounslow West, and most of the people who drive past it on the Staines Road every day have no idea how much ground it used to cover.
In the sixteenth century the heath ran to more than four thousand acres, spreading over land that is now Feltham, Cranford, Bedfont and Hampton. Every coach heading west had to cross it, which is why it collected highwaymen, and it was flat and empty enough for an army to camp on, which Cromwell's did in 1647. Much later it held an aerodrome. On 12 November 1919 the brothers Ross and Keith Smith took off from here in a Vickers Vimy and came down in Darwin about a month later, the first flight from Britain to Australia.
What remains is the part nobody got round to building on. Skylarks nest in the long grass through spring and summer, there are slow worms and the occasional adder for anybody patient enough to look, and aircraft cross the sky to the north all evening, which somehow does nothing to spoil it.
Summer 1784: five miles, measured by hand
The reason a mapmaker belongs in a guide to a TW4 walk is William Roy, a Scottish military engineer who spent the summer of 1784 measuring one straight line across this heath. It ran from King's Arbour, close to the old hamlet of Heathrow, to the poorhouse at Hampton, and it came out at 27,404 feet, a little over five miles. The immediate purpose was to fix the observatories at Greenwich and Paris against each other with a chain of triangles across the Channel. The longer consequence was every Ordnance Survey map made since.
Measuring five miles to a fraction of an inch with eighteenth century equipment meant doing it very slowly. Roy's team began with wooden rods about twenty feet long, discovered that they swelled and shrank with the weather, and replaced them with glass tubes of the same length resting on trestles. Each tube was brought exactly level with the next, the rear one was lifted and carried forward, and the whole operation was repeated well over a thousand times across grass and scrub.
Roy died in 1790. The Ordnance Survey was founded the following year, and his baseline is generally treated as its starting point: the one length that was actually measured on the ground, from which every later triangle across Britain was calculated. Not many stretches of suburban grass can claim that.
Two old guns, muzzle to the sky
In 1791 the two ends of the line were marked with old cannons, sunk upright into the ground with the muzzle pointing upwards. Both are still in place. The south-eastern one stands on a small patch of grass off Roy Grove in Hampton, a quiet residential street named after him, and it is a short drive from the heath if the evening is heading towards the river anyway.
The north-western one is at Heathrow, in a small partly enclosed patch near the Nene Road roundabout on the airport's northern side, with its inscribed slate plaque now mounted on a plinth close by. It is a monument to be seen rather than a place to linger, surrounded by airport roads, and it works best as a curiosity to point out from the car on the way to a room on the Bath Road.
Between the two guns, almost all of Roy's line now lies under houses, roads and runways. The heath is the surviving piece of the open ground he worked across, the place where you can stand in long grass, look towards the horizon and picture a row of trestles heading off into the distance. That, more than any plaque, is the point of walking it.
Why a summer evening here beats any park in TW4
The parks around Hounslow West are pleasant, mown and entirely predictable. The heath is none of those things. The paths wander, the grass is left long, and in June and July the light goes gold across it well into the evening, after the dog walkers have mostly gone home and the loudest thing left is birdsong over a distant road. It feels far bigger than two hundred acres because nothing on it has been tidied.
It is best used as the first hour of a longer evening rather than the whole of it. Arrive while the sun is still well up, walk in from the Staines Road side, take one of the loops out towards the Crane and back, and be sitting at a table by the time it is properly dark. The paths are not lit, the ground is uneven in places, and there is no good reason to be out on the heath once the light has gone.
Shoes matter more than anything else. The paths are firm in a dry spell and very much not after rain. A companion who knows the plan in advance will arrive in something she can walk in and carry the smarter pair in her bag. Tell Iris the heath is on the itinerary and it will be passed on word for word.
Who knows the heath
Roxi crosses the heath most mornings at a speed nobody else out there can match, and she will happily cross it again in the evening at a gentler one. She is two minutes from Hounslow West station and treats a walk as the natural opening to almost anything. Bianka, also anchored on the TW4 side, is the softer choice: warm, talkative and far more interested in the conversation than in the view, which on a heath is not a bad balance to strike.
Laura is based a few stops up the line at Osterley and walks green ground most weeks whether she is working or not, so rough paths and a sky full of aircraft are familiar country to her. Both Bianka and Laura appear on the brunettes page, which is also the place to start if you would rather choose by a face than by a postcode.
Turning the walk into an evening
The natural shape for this is the girlfriend evening: nothing to perform and no itinerary to keep up, just a walk, a table and talk that finds its own direction. Two hours at £500 covers a loop of the heath and an unhurried dinner. Four hours at £900 lets the walk run long, fits in a proper meal on the High Street or down towards Whitton, and means nobody glances at a phone to check the time.
Arrange to meet at the station or at a gate rather than somewhere out on the heath itself; a bench in the middle of two hundred acres is not a meeting point anybody can find. If you are unsure which Piccadilly line stop is nearest your address, the key to the stops between Boston Manor and Hounslow West settles it. The southern edge of the heath is nearer Feltham than Hounslow, which helps if dinner is going to be on that side.
You settle her fee with her face to face in the opening minutes, before anybody sets off across the grass, and after that nobody needs to mention it again. From then on the evening is about skylarks, a slow circuit and whatever the two of you end up talking about.
Filed under: most of the names in this note also sit on the brunettes shortlist in the panel.