Enough of the Thames. The edge of the City bends inland through Middle Temple Gardens, aiming for the very point where Fleet Street becomes the Strand. This spot used to be marked by Temple Bar, the western entrance to the City - originally wooden, then later an ornate stone gateway across the width of the street. When road traffic became important the arched blockage had to go, so it was relocated to Theobalds Park in Hertfordshire and replaced by a tall commemorative plinth. On top is a bronze dragon, very different to all the others to be found around the City's perimeter - more proud, less squat. Most appropriate for the dividing line between political Westminster and big business London, and much easier to drive round.
Chancery Lane's up next. Since 1994 the boundary's run the entire length of the street, whereas before that it wiggled to left and right in an unplanned medieval manner. At the junction with Carey Street outside the Law Society is the precise confluence of Westminster, Camden and the City - a spot also marked by a plaque commemorating the Jubilee Walkway. Various intriguing passageways lead off to either side, well worth a weekday exploration, but for this journey the legal frontages of the main road must suffice. High Holborn creeps up round the last bend, a sudden blast of Starbucks and Specsavers, plus considerably more traffic. The Cittie of Yorke pub isn't as 15th century as it looks, being a 1920s rebuild, although Staple Inn really is Tudor, its gorgeous oak frontage one of the few City structures to have survived the Great Fire.
At Holborn Circus, where a statue of Prince Albert doubles up as a roundabout, we veer left. Not up Hatton Garden, but a full half mile straight along Charterhouse Street. What an eclectic street this is. On the left hand side are former warehouses belonging to the Port of London Authority and "The Central Cold Storage", then several cutting-edge bars and nightclubs. Across on the City side, somehow still standing, the anachronistic sheds of SmithfieldMarket. The General Market building at the Farringdon end has seen better days, and survives solely so that it can be incorporated into some sympathetic future redevelopment. Meanwhile an unmistakeable carnivorous whiff exudes from the Central Market, even at weekends, though don't let that put you off photographing the picturesque cluster of telephone kiosks in the covered arcade.
Crossrail's making its mark along here, with deep interventions in several places which will one day combine to create the ridiculously long Farringdon/Barbican station. Charterhouse Square is rather more peaceful, though definitely pentagonal, watched over by the Art Deco curves of Florin Court. That's the last bit of "comfortable" architecture for a while, because straight ahead are the more brutal towers of the Barbican estate. Its raw-build apartments and windswept highwalks loom large - a modern uprising you'll either love or hate. But rather than heading inside we're turning left, to follow a few hundred yards of the only road in the City of London. Every other thoroughfare within the perimeter is a Lane, a Street, a Yard or something, and quite deliberately not a Road, which makes Goswell Road unintentionally unique.
We've reached the City's northernmost bump, carved out of Islington in 1994 to encompass the whole of the Golden Lane Estate. This is the Barbican's lesser known neighbour, a proper housing estate for more ordinary folk, and constructed approximately one decade earlier. Again concrete is king, with high density maisonette flats leading out to surprisingly green open gardens to create a settlement that would've made Le Corbusier proud. At its heart is Great Arthur House, at 16 storeys briefly the tallest residential building in Britain, still blessed with trademark yellow cladding. It has an acclaimed (but inaccessible) roofgarden, topped off by a curved concrete canopy to cover the water tanks. Enjoy the unexpected suburban panorama as you walk around three sides and back towards the Barbican. And don't think everyone who lives in the City is a banker, far from it.