Victoria Line: Green Park - Brixton

South of Green Park lies the commuter chicken run that is Victoria. Perhaps the best place to view Victoria is from as far away as possible, which conveniently enough is where this picture was taken, from a balcony on the fifth floor of the building where I work.

Any closer and you're likely to get caught up in the tide of 80 million travellers that rolls to and from the place every year. It's been an interchange with the Victoria Line since March 1969, and was the terminus until the Brixton section was fully completed in 1971.

Despite the grand entrance and commanding atmosphere, it's not a nice place, especially during the rush hour when various parts invariably get temporarily closed and great mobs of people are held by staff halfway down some steps or alongside the barriers or, worse of all, on the concourse of the mainline station.

This is ostensibly to prevent overcrowding, but can't help but contribute to the problem by swelling still further the already dense clusters of pugilistic punters. And sometimes the hold-ups can go on for a couple of hours. Electronic hooters and foghorns sound a siren whenever these kinds of operation are in progress, which fuels the hysteria even more.

Something is being done about this. Or rather, people are thinking about doing something about this to ensure an entirely new station is up and running by 2014. It's also the hottest stop on the Victoria Line by far: no mean feat when you consider the competition from its almost equally suffocating rivals. There's a big notice up by the escalators vowing that cooling systems are being 'tested'. The notice has been there for as long as I can remember.

Pimlico, by contrast, is about as timid as they come. It wasn't even part of the original Victoria Line, opening a year after everywhere else, as if the builders decided it wouldn't be missed and they'd come back to deal with it later. Moreover it's the only stop on the line which isn't an interchange. I like its unassuming nature. It sits in an office block that was entirely occupied, up to 2006, by the Office for National Statistics. Pimlico is the only station on the Underground without any letters of the word 'badger'.

It's quicker to walk to Vauxhall, the next station on the line, but then you'd miss out on the treat that greets passengers passing through the ticket hall: unashamed, unadultered classical music, pumped out at full volume through the tannoys. The audacity of this decision is its greatest asset.

I felt even more self-conscious than usual, however, taking this photo. There are security cameras all over the place, both inside and outside, for despite there being no above ground station at Vauxhall, it's right next door to MI6, itself surely one of the most self-conscious "secret" bases in the world.

By this point on the journey, the heat inside the train gets more bearable thanks to it being almost empty; few commuters seem to stray south of Vauxhall, and after you've been through Stockwell - which I've already visited - you're usually alone in your carriage.

Brixton, the terminus, was closed for a while last year while asbestos was removed. It's got a great exterior, comprising chiefly of a massive Underground logo, which is really what you want.

There's talk of extending the track further to Herne Hill, adding a new station as well as a proper loop so trains don't have to reverse before heading back up the line. It'd make sense, because then there'd be an southern interchange with Thameslink services to complement the northern one at King's Cross. Even were this to become the case, however, and even were all the rickety carriages replaced at the same time, I wouldn't be able to find it in my heart to like the Victoria Line until the day someone figured out how to turn the thermostat a degree or so below scalding.