The "Thames Barrier" is a barrier system that is considered a<u> movable one</u>. During high tide, the barrier is opened while during low-tide, it is closed. It started its operations in<em> 1982</em> and since then, it has been helpful in preventing floods to the majority of places in London<em> </em><em>(a city in England).</em>
Clearly, if Thames Barrier failed, then London would be in danger of flooding. Much of this flood would come from the rivers and streams that stretches in most areas of Greater London.
The type of question that the bolded text (" My name is Marcus Yallow, but back when this story starts, I was going by w1n5t0n. Pronounced "Winston." ) can help you answer is literal.