These oddly shaped building features are often overlooked but they hold a special - and sometimes disgusting - purpose. 

By the 1800s, Norwich had become very overcrowded because of a boom in trade and prosperity.

But due to the sheer number of people and lower hygiene standards of the day, public urination was rife throughout the city. 

Urine deflectors were introduced to the city's streets in the 1800sUrine deflectors were introduced to the city's streets in the 1800s (Image: Newsquest) The Victorians called it a "nuisance" and the wall of a yard just off St Benedicts Street still bears the warning "Commit No Nuisance" to this day.

By the mid-19th century, it was so bad that the city decided to do something about it. 

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Architects used a "hostile" style of design to build slopes or curves into the corners with stone, flint or concrete. 

They are usually conical in shape to deflect urine back onto someoneThey are usually conical in shape to deflect urine back onto someone (Image: Newsquest) If anyone tried to urinate on one it would deflect it back at them, staining their shoes and trousers. 

It also forced the more determined urinator to take a step back into the light and risk being seen or worse - caught by the constable.

Some of the designs included metal bars or spikes which could not be seen in the dark and were usually placed at groin height, discouraging any would-be male urinator. 

Deflectors big and small can be found across the cityDeflectors big and small can be found across the city (Image: Newsquest) Not many of these metal designs survived because they were repurposed during the Second World War when iron was in high demand. 

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Most of the time, the deflectors were made from the same material as the building to blend in, such as flint for outside a church. 

One in St Crispin's Road is believed to be Britain's oldest surviving example.

Some were designed to help prevent nighttime crime Some were designed to help prevent night-time crime (Image: Newsquest) And they also served another purpose - stopping thieves and muggers from having a dark corner to pounce on unsuspecting passers-by from. 

This was used to great effect in cities such as Paris where night-time crime rates fell after their introduction. 

But by the 1890s, public toilets had removed the need for them and no more were built, leaving just 30 remaining today.