This colour-coded map shows the speed limit of every road in London. Cool

As ever, in times of darkness, I find myself turning for comfort to cartography. Specifically, on this occasion, it’s a map of London’s road network that’s caught my eye.

Maps of London’s road network are ten a penny of course, but this one’s a special map of London’s road network because it’s colour coded:

The vast majority of roads in the capital are coloured either blue (a limit of 30mph) or green (one of 20mph).

And what you can see is, well, some boroughs have been much more enthusiastic about the “20’s plenty” safety campaign than others:

Click to expand. Image: TfL/Ordnance Survey.

Some boroughs seem to be, main roads excepted, coloued green in their entirity: best I can tell, that covers the City, Southwark, Tower Hamlets, Hackney, Islington and Camden. Others – Lambeth, Lewisham, Greenwich, Newham, Waltham Forest – have large blocks of green, showing that significant chunks of the borough are restricted to the lower speed limits. (UPDATE, 10.42hrs: The map dates from June 2016, so may be slightly out of date: a Twitter user informs us that Lewisham is all 20mph now.)

Central London – click to expand. Image: TfL/Ordnance Survey.

Most of the rest, though, have green in patches, if at all. Of these, by far the blue-est is Westminster, which, despite being right at the heart of London, is blue basically in its entirety. (There may be a couple of streets in the museums quarters just south of Hyde Park, but I’m not entirely sure those aren’t just across the border in Kensington.)

One hates to rush to judgement about these things, but I can’t help but wonder whether there’s any link between this and the fact it’s the Tory-iest borough in central London.

Two other things leap out at me about this map. One is that you can see the colours mean that, in much of town, you can the shape of the main road network: lines of blue snaking through green in inner London, and red or pink snaking through blue in outer. (Once again, Westminster lets us down. Bloody Westminster.)

Hillington – click to expand. Image: TfL/Ordnance Survey.

The other thing that leaps out at me is – stop me if you’ve heard this one before – quite how empty the outermost boroughs are. There are large chunks of white space in almost every border borough, with the possible exception of Sutton; but there are vast swathes of it in Hillingdon (out west) and Havering (out east).