This must rank as one of the least-famous viewpoints in London. We're on Gallions Hill, a manmade structure in Thamesmead West (a little east of Woolwich if you're new to the area).
In a manner similar to Stave Hill in Rotherhithe, the mound is built from the rubble and soil excavated during construction of a nearby housing estate. This was once marshland, so the tor (as it's called), rises up high above its surroundings. Here's the view from ground level.
The housing estate is the Gallions Reach ecopark, sustainable, affordable housing that takes its name from a nearby stretch of the Thames. A DLR station of similar appellation can be found on the other side of the water, making Gallions Reach a rare London place name that can be found on both sides of the Thames.
The southern Gallions Reach enjoys no rail transport whatsoever. The nearest station (Plumstead) is 1.5 km away. (Actually not that bad for Thamesmead, where some houses are 2.5 km from a train station, and next to a sewage treatment works.)
It's easy enough to climb straight up the mound. That would be no fun. You'd miss out on the gradual reveal of the helical path, which twists twice around the hill. Here, looking south, is Plumstead:
More familiar sights can be viewed to the west (top image). The clusters of Canary Wharf and the City are both clearly visible; even distant Vauxhall. The view to the north is also intriguing. Much of the surrounding area remains overgrown and unused. The land is contaminated and peppered with old military buildings, from the days when these marshes formed part of Woolwich Arsenal. In the distance, the Barking Creek flood barrier looms like a guillotine:
The tor is the centrepiece of an emerging expanse of parkland on the western edge of Thamesmead. Numerous smaller hillocks encircle the hill, while a twisting path — not yet fully open — curls off toward the Thames. The so-called Gallions Reach Public Park should not be confused with Gallions Reach Shopping Park, 2km away on the other side of the river.
The wider area is fascinating to explore. Thamesmead proper, to the east, is a mix of housing styles, miles of artificial waterways and an unexpected old clock tower from Deptford.
The site is best approached along the Thames Path from Woolwich, or by following the route of the old Royal Arsenal Canal from Plumstead.