This Graphic Shows How London Could Have Flooded Without The Thames Barrier

Via the Environment Agency.

The Thames Barrier was closed on Thursday and Friday last week, due to severe flood warnings.

Via Twitter: @MPSinthesky

The Thames Barrier is one of the largest movable flood barriers in the world. It protects almost 50 square miles of central London from flooding caused by tidal surges.

Had the 520m barrier not been closed, this is how London could look.

Environment Agency

The picture was released by the Environment Agency to show what flash flooding could do to the capital.

"We estimate that at least 800,000 homes and businesses have been protected by flood schemes in the past 24 hours," said Dr. Paul Leinster, the Environment Agency's chief executive.

But although London was saved, the tidal surge caused chaos in some of the country's coastal areas.

It was the most serious tidal surge the U.K. has seen in over 60 years.

This was the scene in Rhyl, on the north east coast of Wales.

Getty / Christopher Furlong

This was the storm's aftermath in Eyemouth, on the Scottish border.

Getty / Christopher Furlong

And this is what New Brighton, on the north east coast of the Wirral looked like.

Via Twitter: @NinaStobart

Thousands of U.K. residents have been evacuated from their homes, and a huge clean up operation is still in progress.