This hand-drawn map from Wonderful London Volume 2 (published circa 1926) shows the Central London tributaries of the Thames – the Effra, the Neckinger, the Falcon Brook, the Wandle. North of the Thames we have the Counters Creek (here marked Bridge Creek), the Westbourne, the Tyebourne, the Holebourne (River Fleet), and the Walbrook. The contours show the high ground where the springs bubble up to the surface and then helped shaped the city we live in today even though all but one of them has been buried beneath the ground (the Wandle being the exception).

In the essay accompanying these illustrations, Alan Ivimey describes the fate of these Thames tributaries:

“They are right in the very heart, or, more accurately, in the bowels of London. For the fairest of these streams have been obliterated from the face of the earth to become dirty drains beneath its skin, or at least emaciated trickles writhing feebly in what remains of their old beds towards the everlasting Thames.”

This simple sketch simply shows the shape of the Thames basin as a cross-section where many further London rivers and tributaries rise and flow. We see the high grounds of Addington Hills near Croydon to the south and Totteridge, Hendon and Hampstead to the North. Herne Hill and Crystal Palace form the highlands of the inner South of London with Primrose Hill marking the highground of North London just beyond the congested centre.

Ivimey describes how London might have looked when the rivers ran freely through the fields:

“In the lush meadows of Westbourne, near the highway to Harrow, the citizen of London could once see dragonflies and loosestrife, or, lying face down in the buttercups, tickle a brace of trout against the coming Friday.”

We rarely think of London in terms of its topography, flattened out in our minds by tube journeys and bus routes. Cross city cyclists tell a different story, feeling the river valleys in their tightening calves. For the walker the shape of London is unavoidable – ascend one of the peaks in this drawing and you’ll see the city revealed.