The Thames Path starts (or ends) at the Thames Barrier, 180 miles downstream from the river's source. Heading west along the south bank of the river it curves first around North Greenwich, home of the Millennium Dome, and then around the Isle of Dogs. The path frequently diverts away from the river due to property development - East London is filling with luxury flats which are snapped up by foreign billionaires and rented to workers who have given up on even getting a glimpse of the property ladder.

Eventually the Path reaches the City itself. I take a brief break in a pub on Tower Bridge before continuing for another mile or so, ending the first leg of my journey at St Paul's Cathedral.