A couple of years ago I wrote a post asking Where are London's largest circles?
(The Inner Circle in Regent's Park, diameter 330 metres, we decided)
Today I'm trying something similar but one dimension less.
Where are London's longest straight lines?
Could be a road, could be a railway, could be a waterway, could be any surface feature that's perfectly straight. What are the longest lines you can see straight down without a minor bend or wiggle?
A little thought should suggest that London's longest straight lines are probably a) artificial b) quite flat c) quite old. A long time ago it was easy to draw a straight line across the landscape because there was nothing else there, but the amount of undeveloped space has shrunk with every passing decade making twists and curves more likely.
I got the idea for this post from the railway viaduct between London Bridge and Deptford. It's broad, straight and carves across Southwark for 3½ miles with a total disregard for what was there before. You can ride it on a train or follow the line of arches at ground level, because it's been there since 1836 and everything else has moulded around it. But if you drop a straight line onto Google Maps with one end at London Bridge and the other at Deptford it turns out the viaduct's very gently curved, or maybe three or four straight sections imperceptibly linked, so not geometrically perfect. You could allow it because it's really close, but I can only find a mile or two that definitely fits the bill.
So my apologies, this is all going to have to be annoyingly subjective.
Watling Street(Edgware Road) (the A5)10 miles
London's longest straight line was always going to be a Roman road. The Romans arrived 2000 years ago so got to build their famously straight roads wherever they liked, in this case on a beeline for St Albans. It is astonishing to think that their decision still shapes northwest London to this day. But alas Watling Street isn't quite as straight as you'd assume, only very nearly so. It contains a slight bend in Maida Vale (by the Regent's Canal), a more serious mild slalom through Kilburn (courtesy of the River Westbourne?) and a minor modern deviation at Staples Corner. The longest undeniably straight section is the 2½ miles from Kilburn High Road station to Cricklewood, which is still an impressive length... or you could take a less pedantic view and claim the full ten miles.
Watling Street(Shooters Hill Road etc) (the A207)6½ miles
London's second longest straight line is the same Roman road but on the other side of the capital. The road to Dover runs almost arrow straight from Blackheath Royal Standard to the foot of Shooters Hill, then up and over, passing through Welling and Bexley before a modern bend impinges in Crayford. Six and a half miles of straight line is an impressive length to leave across a landscape. Again there are minor issues, most notably a short curve near the Nags Head pub in Welling, but the Broadway Shopping Centre (and Bexley's pedestrianisation) has knocked it off line too, so a mathematician might only accept the 2½ miles from Woolwich Common to Welling.
Lea Valley Line(Tottenham Hale - Ponders End)4 miles
London's longest straight railway, and its longest undeniably straight line, runs up the Lea Valley to the west of the big reservoirs. In a flat valley the most efficient way to join two stations is usually a straight line, which is exactly what engineers created between Tottenham Hale and Ponders End. The straight section north of Brimsdown is much longer, but doesn't quite hit two miles before it crosses the border into Hertfordshire.
New North Main Line(Perivale - Northolt)3.6 miles
The New North Main Line runs from Old Oak Common to South Ruislip and since 1948 has been paralleled by the Central line's West Ruislip branch. It's almost straight all the way but in reality it's three straight lines, the first from North Acton to the River Brent and the third from the Yeading Brook to West Ruislip. All three sections are long but the longest is the middle one, which you'll have followed if you've ever ridden the Central line between Hanger Lane and South Ruislip. One day HS2 will follow this same alignment too (and has already severed the National Rail connection to the south).
North Kent Line(Woolwich Arsenal - Belvedere)3.5 miles
A lot of online measuring suggests to me that London's third longest straight railway line is the one that runs south of Thamesmead. Crossrail will be following half of it, but the whole thing's well over three miles.
District line(Bromley-by-Bow - East Ham)2.8 miles
I wasn't sure which straight bit of the eastern District line would be the longest but it turns out it's the Newham stretch (2.8 miles), which narrowly beats Upney to Dagenham Heathway (2.6 miles) and also Dagenham Heathway to Elm Park (2.1 miles).
The next three are also railways... South Western Main Line(Raynes Park - Berrylands)2.8 miles Great Eastern Main Line(Gidea Park - edge of London)2.5 miles Great Western Main Line(Hanwell - Southall)2.5 miles
Heathrow Runway 09L/27R 2.4 miles
Yes of course this is in the list, and it's a genuine straight line too. Heathrow's north runway stretches across an inordinate amount of former farmland and is marginally longer than its southern twin (2.3 miles). It also defines a flight path which, if I hadn't restricted myself to surface features, is arguably the longest straight line in the capital.
South Eastern Main Line(Chislehurst - Orpington)2.3 miles
Back to the railways. Although the full eight miles southeast of Hither Green looks pretty straight, only the section through Petts Wood genuinely is.
Meridian Way (A1055)2.2 miles
The first non-Roman road in the list is a 1980s link road in the Lea Valley, specifically the section between Meridian Water and Ponders End. It's no coincidence that it runs alongside the longest straight railway line in London.
Greenway (Plaistow - Beckton)2.1 miles
And yes, the Northern Outfall Sewer makes the cut. It has a few bends but the last stretch down to the sewage works in Beckton flows for just over two miles... assuming you can accept the A13 roundabout intruding midway. If not then its southern counterpart the Ridgeway manages exactly two miles... although again with the odd surface blip.
HS1/Tilbury Loop (Rainham - edge of London)2.1 miles
We've had HS2 so here's HS1, flying low across the Rainham Marshes beside the A13 viaduct. The road bends but the local and international railways are straight and just scrape over 2 miles before reaching the Greater London boundary.
If I'm being really pernickety the Lea Valley railway line wins.
If I'm being a bit more tolerant it's Watling Street instead.
My attempt at a map of the longest straight lines is here.
...at least until I'm told otherwise. If you do have any suggestions remember they have to be actually straight, not roughly straight, and also need to be at least two miles long.
