https://www.google.co.uk/maps/place/The+Thames+Barrier/@51.4950977,0.0426551,3a,15y,35.34h,119.51t/data=!3m8!1e1!3m6!1sAF1QipO3SwmKNd3EjUDMPxgXmESUPjjn9aErtiNxQ3oI!2e10!3e11!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipO3SwmKNd3EjUDMPxgXmESUPjjn9aErtiNxQ3oI%3Dw203-h100-k-no-pi-0-ya141.25473-ro-0-fo100!7i13312!8i6656!4m12!1m6!3m5!1s0x47d8a86645de7e2d:0x9bc80086a2472492!2sThe+Thames+Barrier!8m2!3d51.4969707!4d0.0369474!3m4!1s0x47d8a86645de7e2d:0x9bc80086a2472492!8m2!3d51.4969707!4d0.0369474

additionally, is that part of some sort of alarm/smoke-detector system, dazzlenation?....see previous post....go figure: