London's new 'super sewer' to end Thames pollution blight

The door of the steel box lift clanks shut and a crane slowly lowers construction workers building London's "super sewer" 40m to the bottom of an enormous vertical shaft.

LONDON Here, a world away from the city's busy streets, thousands of engineers and construction staff have spent the past seven years creating the biggest-ever upgrade to the city's 19th-century sewers.

London's existing sewerage network dates back to the second half of the 1800s, when it was designed by civil engineer Joseph Bazalgette in response to the in famous "Great Stink".

In July and August 1858, a combination of soaring temperatures and a sewerage system that emptied straight into the Thames resulted in the city being engulfed in a cloud of putrid air.

The unbearable stench led to the construction of the sewerage system that is still in use today.

But in recent decades, lack of capacity due to the British capital's population growth has meant that raw sewage has once again flowed into the river.

Although an engineering wonder of the 19th century, Bazalgette's network used the same pipes to transport both sewage and rainwater, resulting in effluent often spilling into the Thames due to lack of capacity.

"Any time it rains, even a light drizzle, the sewers fill up and pour directly into the river," said Mr Taylor Geall of the construction firm Tideway, which is behind the project.