The use of 'spit hoods' on suspects as they are being arrested by Derbyshire police has more than trebled in the last two years.

Officers from the force have needed to use the masks, which cover the mouths of suspects to stop them spitting at officers, 16 times in 2017 up to January 31, 2018, a Freedom of Information request has revealed.

This is compared to five times in 2015 and another five times in 2014. In 2016 they were used only twice and in 2013 to 2014 they were needed three times.

Superintendent Tracy Lewis, Derbyshire police's head of criminal justice, said: "The decision was taken to issue spit guards to all operational uniform officers, Police Community Support Officers and some non-uniformed officers [dependent on their role] in April 2017.

Police are using spit hoods more often

"This came as a response to a number of incidents where officers were subjected to unpleasant and unavoidable assaults, by being spat at or vomited on.

"The issue of spit guards ensures officers are able to protect themselves from harm when there is a clear and imminent threat of being assaulted in this way. Guards should only be used when absolutely necessary and proportionate to the situation.

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"Officers are provided with clear guidance and instruction on how to use spit guards and every use of the guard is subject to a Use of Force report to ensure we are using them correctly."

Spit hoods are made from a mesh fabric which is placed over the heads of suspects to prevent spitting or biting.

They can only be used once and are usually used in custody suites or when moving people in custody from one location to another. The aim is to prevent the risk of infections such as hepatitis which can be passed on through the saliva.

The spit hoods have previously received some criticism for being "distressing and humiliating", with complaints that they could cause panic in the person being detained.

Police in forces across the UK also have other items at their disposal to protect themselves while on the beat. This includes pepper spray, batons and tazers if they are needed when out on the streets to keep themselves and members of the public safe.