In terms of postcodes they don't, because the 'N' postcodes and 'S' postcodes never touch.
But there are two spots where three postcode compass points meet, and they're the red dots on this map.
The point where South meets West meets East is in the middle of the River Thames. It's almost exactly the same spot where Westminster meets Lambeth meets the City, and is less than 100 metres from the centre of the Garden Bridge, should that ever be built.
But you can't actually visit South West East London unless you're in a boat, so I'm giving it a miss.
Instead I've been to the point where North, West and East London meet - that's the top red dot on the map. What's more it's nowhere important, it's an obscure road junction on a side street, about half a mile from the Royal Mail's largest London sorting office. And it looks like this.
This rather splendid row of Georgian townhouses is in Finsbury, near Angel, just off the Pentonville Road.
The houses on the left are in East London. This is Amwell Street EC1, named after one of the sources of the New River which ends at the bottom of the road. It's a broad and desirable thoroughfare with smart sash windows and basement flats, and small independent shops of the type that the Evening Standard likes to gurgle about. There used to be a Post Office a few doors down but that closed ten years ago.
The houses on the right are in North London. This is Claremont Square N1, a fractionally more upmarket location with terraces of smart villas around three sides. In the centre is a covered reservoir, 55 metres square, built by the New River Company in 1855 to store and filter their water supply. Concealed beneath a raised mound of grass, the reservoir is reputedly made from four million bricks, and is still in use today.
The road leading off inbetween is in West London. This is Cruikshank Street WC1, a short one-way street of elegant 4-bedroom maisionettes with a classical touch. Originally called Bond Street, it was renamed in 1938 to honour 19th century caricaturist George Cruikshank who lived nearby. At the foot of the street is BevinCourt, a striking Y-shaped block of Modernist social housing designed by Berthold Lubetkin.
This quiet corner of Islington is the only place in London where the street signs have postcodes starting with N and W and E. It is the very kind of location that tends to make urban psychogeographers very excited.
I stood on the street corner for a few minutes attempting to channel the creative tension and cultural disconnect, but felt nothing, which isn't surprising because postcodes have no bearing on anything other than how residents' letters are sorted. But this is the precise point where North, West and East London meet. For what it's worth.