London has always been in danger of being flooded by the River Thames overflowing. The main danger comes from tidal surges making their way up the river from the North Sea. It has only been since the construction of the Thames Barrier that the city has been able to breathe a sigh of relief.
However, in the nineteenth century, London’s new sewer system was installed and this included the building of the Embankment along the river in Central London. Although a new sewer was desperately needed, it also brought with it a problem. Its construction meant that the Thames became narrower and deeper. If the river now experienced a tidal surge, there was a much greater chance of it flooding the metropolis. And considering London now had an Underground system of trains, any flood waters could claim many lives.
What was needed was a form of early warning system if the waters were rising to danger levels. The answer to the problem was not only simple but cheap as well. If you look over the Embankment walls today, you can still see what was done. Every few metres there is a mooring point for boats set into the wall. They are in the shape of a lion’s head with the mooring ring extending from its mouth. Mooring points and a river; that all makes sense until you realise they are set at a height which makes them useless as mooring points.
Their real function is to mark the level at which to sound the alarm if the water level reaches them. And until the building of the Thames Barrier, it was part of a policeman’s duties to check the water level as they walked their beat. If the lions were in danger of “drowning” the alarm would be raised and the Underground would be cleared. And if the Barrier should ever fail, well we still have the lions ready to do their work.