Sometimes you'd like to walk/cycle/ride/drive from point A to point B but you can't because something's in the way. The Thames is London's most obvious obstruction, but other barriers to transport are major roads, waterways, railways and airports. This post is an attempt to list London's worst offenders.
London's hardest things to cross
1) The Thames a) The most significant natural barrier in London is the River Thames... and the longest impossible-to-cross section is downstream from Woolwich. It's 8 miles from the Woolwich Ferry/Woolwich Foot Tunnel to the edge of the capital (and 10½ miles to the final crossing point at the QE2 Bridge). It remains impossible to walk/cycle/ride/drive from Bexley to the neighbouring boroughs of Barking & Dagenham and Havering (and will long remain so because a half-mile-wide estuary is an expensive thing to cross). No other obstruction in London comes close. b) Upstream the next impassable gap is the 2½ miles from Woolwich to North Greenwich (where the Blackwall Tunnel/Jubilee line/Dangleway allow drivers/passengers/pedestrians/cyclists to cross). c) Drivers cannot cross the Thames between the Rotherhithe and Blackwall Tunnels. By river that's a 4½ mile gap (but as the crow flies only two). d) Pedestrians and cyclists unwilling to risk the Rotherhithe Tunnel have no way of freely crossing the Thames for the 4½ miles from the Greenwich Foot Tunnel to Tower Bridge. e) Heading upstream, the next significant crossingless gaps are to either side of Hammersmith Bridge, both of which are in excess of a mile and a half. With that bridge currently closed to vehicles, drivers face a 2½ mile (straight line) gap between Putney and Chiswick Bridges. f) The Thames cannot be crossed for the 2½ miles from Kew Bridge to Richmond Lock. g) From Richmond Bridge to Kingston Bridge the Thames forms a 4½ mile barrier to drivers. Teddington Lock provides a shortcut for pedestrians and cyclists after 3 miles. Hammertons Ferry is sometimes available after one mile.
2) The Lea
The River Lea is crossed in surprisingly few places on its 13 mile journey from the edge of London to the Thames, with a chain of reservoirs the greatest barrier. a) No roads cross the Lea Valley in the 3 miles between the M25 and Ponders End. b) No roads (and no footpaths) cross in the 2 miles between Ponders End and the North Circular. c) No roads cross in the 2 miles between the North Circular and Tottenham Hale. d) No roads cross in the 2 miles between Tottenham Hale and Lea Bridge (although three railways do). e) No roads cross in the 1½ miles between Lea Bridge and Temple Mills. f) Only a dead end and a private road cross in the 1½ miles from the Bow Flyover to the A13.
3) The Roding
The River Roding is crossed in very few places on its 8 mile journey from the edge of London to the Thames. For drivers the sole crossing points are Chigwell Road, Charlie Brown's Roundabout, Redbridge Roundabout, Romford Road (Ilford), London Road/Town Quay (Barking) and the A13. The longest gap is 1½ miles between Redbridge and Ilford. Pedestrians/cyclists also get footbridges in Woodford(1), Redbridge(2), Wanstead(1) and Barking(2). There are four railway crossing points. But that's it.
4) Rivers in Havering a) The River Beam is crossed by zero roads during the 2½ miles between Romford and Dagenham (and by the District line and three minor footbridges) b) The River Ingrebourne is crossed by zero roads during the 2½ miles between Hornchurch and Rainham (and only two footbridges).
5) Rivers in Barnet a) Only one road crosses the Dollis Brook in the 3 miles from Hendon Wood Lane to Whetstone. b) No roads cross the Folly Brook in the 2½ miles between Mill Hill and Woodside Park.
6) Grand Union Canal a) Only one road (the Uxbridge Road) crosses the Grand Union in the 3 miles between Greenford and Bull's Bridge. b) Only one road and the M4 cross the Grand Union in the 3 miles between Southall and Brentford.
7) Major roads a) Only one road crosses the A40 in the 3 miles from Northolt to Hillingdon. b) Only one road crosses the M4 in the 2½ miles from Heston to the Chiswick Flyover. c) Only one road crosses the North Circular in the 2 miles from Strawberry Vale to New Southgate. (This inspired today's post) d) No roads and no footpaths cross the A13 in the 2 miles between Rainham and Wennington.
8) Railways
Lots of railways are hard to cross, especially when they're at ground level or on long embankments. a) The longest railway-related severance I can find is the 2 miles between Tottenham Hale and Lea Bridge, which crosses no roads (and has only four crossing points on foot). b) There are 1½ mile roadless gaps between Kenton/North Wembley, Newbury Park/Fairlop, Grove Park/Elmstead Woods and Rainham/Purfleet. c) There are almost 1½ mile roadless gaps between Clapton/St James Street, Totteridge & Whetstone/High Barnet, Meridian Water/Ponders End, Albany Park/Bexley and Bickley/St Mary Cray. d) Only two roads cross the Great Western Mainline in the 3 miles between Southall and Hanwell.
9) Heathrow Airport
Heathrow, which is 3 miles across and 1½ miles wide, cannot be crossed on foot or in a private vehicle, only by train (or possibly in an aircraft).
10) Open land a) Although Richmond Park is freely accessible on foot, it creates a 2½ mile-wide obstacle for motor vehicles. b) Kew Gardens/Old Deer Park and Wimbledon Common/Putney Heath are both 2 miles across, and Hampstead Heath 1½ miles. c) A 4½ mile straight line drawn from Hainault to Noak Hill is crossed by only one road, at Havering-atte-Bower.
I'm sure I've missed a few, so do let me know.
n.b. You can explore severance lengths for yourself on this measurable version of OpenStreetMap.
n.b. I'm not really interested in severance of less than two miles (1½ miles for railways).
n.b. I'm only really interested in lines which represent physical features.
n.b. I've ignored severance on the boundary of Greater London.
n.b. My measurements are all approximate.
n.b. I have not been over-pedantic.
