Ostensibly there's nothing confusing about it at all. It is a straight line. It has no branches or curious offshoots. It doesn't even have that many interchanges.
When I started reading up on this bit, though, a familiar tale of multiple name-changes, disputed ownership and successive renovations emerged. It didn't even used to be a straight line.
It is, however, indisputably old. Very very old. There's been a station on the site of Tower Hill since 1882, when the Metropolitan Railway opened the matter-of-fact sounding Tower of London. This lasted all of two years before being closed to make way for Mark Lane station. The reason? The Metropolitan had just linked up with the Metropolitan District (now the District Line) to give birth to what was informally dubbed the Inner Circle, and a larger station was needed.
Mark Lane became Tower Hill in 1946, a year before the Inner Circle became the official Circle Line. But still the station was too small, so it was closed and rebuilt yet again in 1967, back on the old original Tower of London site. 41 years on refurbishment work is STILL happening, because the station is STILL too cramped and creaky.
Tower of London would make for a much better name than Tower Hill. It must be one of the stations most visited by tourists, and shouldn't hide its importance behind a misleading moniker. When I took this photo, on a Friday evening, 100 French teenagers were swarming outside.
Here's Monument, from an afternoon in the summer of 2007 when the Standard was essaying its usual thirst for BBC-baiting:
The station was expressly built for the new Inner Circle, opening in 1884 with tracks freshly-laid between Aldgate and Mansion House to complete the loop. This hadn't been an easy process. The two companies, the Metropolitan and the Metropolitan District, had fussed and feuded over who would build the final stretch of the circle, the precise route from one bit to the other, how much it would cost and so on. It was typical of the times that the construction of one bit of track encircling the centre of London involved two companies, big business, the government and endless delays.
Monument nowadays is part of the sprawling network of tunnels and escalators that link it with Bank. It feels like it doesn't have an identity of its own. It's so close to its neighbours, it's almost worth avoiding altogether. But that would mean having to use the monstrosity that is Cannon Street:
There was once a great building above this station, built on the site of the medieval Steelyard, the trading base in England of the Hanseatic League. It had giant towers, a huge curved roof for the mainline platforms, and a splendidly lavish hotel in the style of Charing Cross and Baker Street.
Then it fell into disrepair. Then it suffered bomb damage during the war. Then the rascal architect John Poulson knocked the whole thing down and built one of the worst stations anywhere in Britain.
It being dark when I visited, you're spared the sight of the offensively boring slab of dullness that is the present-day outside of Cannon Street. It is a building that has no redeeming features. It is horrible. It is menacing. And thankfully, finally, it is about to be pulled down. What this means for the underground station isn't clear; at the moment all you do is walk through what feels like a empty grain silo or abandoned warehouse and down some steps. Hopeless.
Mansion House must surely be the only London Underground station mentioned, albeit indirectly, in the lyrics to a children's TV programme (Rentaghost). It opened in 1871 as the eastern terminus of the Metropolitan District Railway, and was done up in the 1920s by Charles Holden.
It's part of a sequence of stations that sit on the banks of, or very close to, the Thames, but which seem to patronised chiefly by city-folk and business types. They all have an air of creeping panic to them. The platforms are dank and have the ambience of an Edwardian municipal swimming pool. Nobody lingers, except to speak briskly on a mobile phone before plunging below. You're not encouraged to pause or drag your step. And you won't see one friendly, smiling face.
Blackfriars is a soulless cavern. It's also due for major renovation, to the extent that the whole Underground station will close from March 2009 to late 2011. The plans sound promising, and include a new entrance on the South Bank, i.e. the other side of the river, making it the first station you can enter from either side of the Thames.
Temple's got a bit more character. It's been around since 1870 - when what became the Inner Circle first started to creep eastwards from Westminster - and you can palpably sense its history from its look and feel. At one point this was going to be a terminus for the Piccadilly Line, before somebody changed their mind and halted at the now-abandoned Aldwych instead. The two are only 200 metres apart.
I passed through Embankment on the Northern and Bakerloo, and have already talked a little about its garbled history. By the time it became an interchange with those lines it had already been open for over 30 years and was firmly established in the passenger mind as Charing Cross station. It was only when the Bakerloo arrived in 1906 and decided to call the place Embankment, when it wasn't, that the garbling began.
No such confusion with Westminster:
Well, except it opened in 1868 as Westminster Bridge. And it used to be the end of the line. If you were travelling from the west. And only until 1870, when Blackfriars became the end of the line. And was nothing to do with Westminster Bridge Road station, which opened in 1906, but which had previously been called Kennington Road, and which later changed its name to Lambeth North, by which point Westminster Bridge had become Westminster, so it didn't matter anyway.