Dartmouth Park is one of those residential London suburbs that I bet you've never heard of, probably because it doesn't have its own station. It lies south of Highgate, west of Tufnell Park and north of Gospel Oak, clinging to the eastern edge of Hampstead Heath. The gated avenues to the north are lined with exclusive suburban mansions and mock Tudor apartments, whereas the terraces to the south are rather more ordinary. It's also one of the best places in the capital for Fleet spotting. Look carefully and the former path of the river becomes blindingly obvious from the contours of the land. Several local roads dip down as they cross York Rise, revealing very clearly that a long-lost river once took this path down the hillside. Along the former riverbanks there's a tasteful old gastropub (the DartmouthArms) and, up the side wall of Roots hairdressing salon, a lovely faded painted advert for KM Lann outfitters [FANCY WORK, CORSETS, GLOVES, HOSIERY, LACES, RIBBONS, HABERDASHERY, FLANNELS, FLANNELETTES, CALICOES, UNDERCLOTHING, MAIDS' DRESSES, CAPS & APRONS]
But my most exciting find in Dartmouth Park was at the foot of York Rise, where a graffitied footbridge crosses the Gospel Oak to Barking railway line. There are two pairs of tracks, the southern running though a cutting much lower than the northern, and it seems unlikely that any underground river could pass beneath this manmade chasm. And so a big black pipe bursts briefly from the railway embankment, arching up over the tracks alongside the footbridge before plunging back down into the earth. It's very short, it's seen better days and it's well hidden beneath a leafy canopy, but I'd lay money that this ancient pipe carries the remains of the river Fleet. Above ground. It seems that even the deepest subterranean rivers have to pop up for air occasionally. Following the Fleet: Swain's Lane, Brookfield Road, York Rise, footbridge, Ingestre Road, Burghley Road