Westminster Bridge is a road-and-foot-traffic bridge over the River Thames in London, linking Westminster on the west side and Lambeth on the east side. The bridge is painted predominantly green, the same colour as the leather seats in the House of Commons which is on the side of the Palace of Westminster nearest to the bridge, but a natural shade similar to verdigris. This is in contrast to Lambeth Bridge, which is red, the same colour as the seats in the House of Lords and is on the opposite side of the Houses of Parliament.
https://en.wikipedia.org/wiki/Westminster_Bridge