Sometimes, when people say something is "secret", they mean it's little-known or hidden. But
this actually is a secret.
In the Second World War, Britain had a problem: getting fuel from refineries to airfields
up and down the country. Above-ground transport of fuel was too vulnerable to well-placed
bombing of the road network. Not to target the tankers themselves, but to make the roads
they used impassable. The solution: build an enormous top-secret, underground pipeline
network to carry aviation fuel across the country. It was even built at night so enemy
reconnaissance aircraft wouldn't be able to tell what was going on.
Over the decades since, this network has been expanded and expanded and expanded, until
it became 1500 miles of pipes, that connect seaports, airports, fuel refineries, and Air
Force bases across Britain. It's vital for both military and civilian use: when your
plane's being refuelled at any major British airport, that fuel is coming from tanks that
are connected straight to this pipeline network.
Airports in other countries have similar systems, but they're smaller, private arrangements.
This was one big, top secret, government network -- in fact, until it was sold off and privatised
in the last few years, the Air Force flew over most of the network regularly just to
make sure all was well.
Now, the pipeline's public knowledge today, because, well, you can't keep something as
big as that secret any more. You can see the schematic, like a vague subway diagram, and
there are a few well-documented places, like here near Gloucester, where it pokes above
ground for a few metres. But there is no public map of exactly where the pipelines lie. In
2010, the government refused to answer a Freedom of Information request for that map, on the
grounds that it would affect national security and defence. And, to be fair, it would.
But at the same time: anyone local might well need to know where that pipelines is, just
so a construction worker with a drill doesn't suddenly break a pipe, and spray high pressure,
highly-flammable aviation fuel all over the place, and stop Heathrow Airport for a day.
So all the pipes have these markers above them at regular intervals -- sometimes these
small ones you can see in the back, but often these massive posts. Most people will see
them just as street furniture, if they notice them at all, but if you're a professional
surveying the area round here ready to dig, that's a big warning sign that, perhaps, you
might want to double-check exactly what's below ground here.
Now in theory, someone could use modern aerial and street photography, work out the routes,
and publish them anyway -- and a few enthusiasts have done that for their local area. But you
won't see any official confirmation of that, because for once, this pipeline really is
a secret.
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