United Kingdom Thames Barrier South Side, London

This is the harder side of the river to get to but probably slightly better for photography than the north side because the sun should be behind you. Other than the position of the sun, I don't think there's much to choose between the north and south sides. The spot itself is a small patch of land with railings at the edge of the river. I was there with a photography workshop group for about an hour and we didn't see another person the whole time - you can set up your tripod here without being bothered. It's a bit of a pain to get to but worth the effort.

This shot was taken at dusk, I've never tried it at other times of day and this was taken a while ago, but I think the sun was setting behind me. It was a cloudy day so didn't get a sunset but on a better day the clouds in the shot should light up at sunset.

This shot was taken at low tide and you can see the riverbed is partially exposed. I'd recommend going at high tide for a cleaner composition.

Full disclosure: there was an ugly wooden post near the middle bottom of this composition which I have cloned out. I think it would be hidden at high tide, but at low tide it was ruining the composition.

This shot definitely lends itself to long exposure, so use a powerful ND filter (this particular shot was 8 minutes, though you wouldn't think it because the clouds were refusing to budge).

This spot is harder to get to than the north side because it's not really served by the London Underground. The best route by public transport is to take the Jubilee Line to the Millennium Dome and then the 161 bus - it's still then about a 10 minute walk from the nearest stop on the bus route.