If you've come to this page from a search engine, the clock itself is here!
This should work in all modern web browsers, mobile & desktop. I haven't tested Internet Explorer 11 as I write this, though I've tried my best to make sure it works there too. Bug reports are welcomed.
The second hand appears to move in a continuous sweep. It's actually every 1/50 of a second (20 milliseconds). This is slightly slower than the refresh rates of most modern computer & device displays (and much slower than 120 Hz mega-displays), which is why it might feel a little janky or hesitant. This is intentional!
Why 1/50 of a second? These clocks were synchonised by the mains AC cycle, which in the United Kingdom is 50 hz (50 cycles per second).
At zero and thirty seconds, the minute hand is advanced by half a minute (3 degrees), and the hour hand is advanced by a hundred and twentieth of an hour (0.25 degrees).
A few days before I officially released this clock, I sent the link to a few people for their opinions, and they passed it to some other people, and even before I officially released it I received a couple of emails asking if I would release this as an app and/or widget for phones & tablets.
Writing an app and/or widget for phones would require re-writing it at least twice; once for Android, once for Apple devices. I optimise for the reaching the largest number of people.
Writing this for the web means I write it once and it works everywhere.
Writing it for the web means that anyone can see it and play with instantly.
Writing it for the web means that anyone can grab the code, tweak it, and find new and creative things to do with it. (For you techie people out there: this is why I have not minified the code, why there is no build system, and why it is all in one self-contained monstrosity of an HTML file. I have optimised for ease of play & tweaking.)
A native app probably won't happen, because I have no interest in making one. But I sincerely hope the code might give someone an idea or two. (See "Copyright" below; this is explicitly encouraged.)
This project would not have been started were it not for Nick Job, who accidentally inspired this project with a tweet. Nor would it have been possible to make this reproduction without his comprehensive digitisation of the British Rail Corporate Identity Manual, which was used as the primary reference material for this project. Check out his definitive website and follow him for plenty more BR-era goodness on Twitter. (Any inaccuracies are entirely my own, and not a fault of his impeccable digitisation.)
Suggestions are most welcome by email, or as bug reports on GitHub.
A Network SouthEast Clock.
The code for this clock is in the public domain. I encourage you to steal my code and/or ideas therein for your own projects. You may use it, with or without modifications, for any purpose.