The top one is the general view; the bottom one is zoomed-in. As you can see, some of the bricks have initials on them.
The story goes that there were arguments between the governing parties of Colchester when the tower was built. The Liberals were for it, the Conservatives against. The Liberals won, but the Conservatives weren't finished in their objections. When the Liberals wanted a ceremony to mark the start of building work, the Conservatives complained about how unnecessarily expensive it would be, and dug in their heels. The Liberals had to raise separate funds just for the ceremony, which took time, but this still didn't please the Conservatives. The Liberals said OK, we'll have an opening ceremony without you, at which point the Conservatives caved in.
Meanwhile, the building work had continued apace. By the time the local politicians had agreed to have a ceremony, commemorating their contibutions with bricks bearing their initials, the building was already quite high. They had to climb up ladders and scaffolding wearing their best suits and top hats in order to lay their bricks. This was nevertheless preferable to chiselling out their initials themselves on lower bricks.
So it is that the initials of the councillors who were involved in the construction of Colchester's water tower are on bricks 20 feet up in the air.
This is all according to the guide who showed us around the tower when we went up it last month. I'm sure he didn't embellish his explanation in the slightest.