The controversial restraint devices were made more widely available to officers at the end of March by Chief Constable Simon Byrne with support from the Northern Ireland Policing Board.

Amnesty International has previously raised human rights concerns about the devices, particularly in respect of the risk of restricting breathing and causing extreme distress to the wearer.

The human rights group has been engaged in “detailed correspondence” with the PSNI over the roll-out of spit hoods and said the force had now admitted there was no public health basis for their increased use.

In a letter sent on 9 June 2020, the PSNI told Amnesty that the manufacturer of its Spit-Guard Pro devices had acknowledged that they are “not an effective means to prevent COVID-19” because they do not “prevent aerosols from coughing or sneezing”.

Amnesty believes the devices could in fact increase the risk of police officers contracting COVID-19 because the process of fitting the hood is likely to result in a “cloud of virus particles”, as any struggle is likely to be a “significant aerosol generating event”.

Oliver Feeley-Sprague, Amnesty’s UK policing expert, said: “Spitting and threats to infect people are abhorrent, but spit hoods are not PPE and could put officers in greater peril.

“This new admission from the manufacturers that the devices will not stop the spread of this deadly virus is startling, especially for any police officers who might have previously been under the impression that these devices would help keep them safe.

“Spit hoods could actually be seen as an un-safety device and police chiefs should make it crystal clear to all their officers spit hoods do not offer any protection from COVID-19 transmission or infection. Police forces across the UK should now withdraw them from use in possible or suspected cases of COVID.”

Patrick Corrigan, Amnesty’s Northern Ireland programme director, added: “The pandemic has been used as cover to roll out these controversial restraint devices in Northern Ireland in the face of the scientific evidence.

“Now it turns out, as Amnesty pointed out from the start, not only do spit hoods not protect police officers, but their use could actually put them at increased risk of contracting COVID-19.

“We would urge the Chief Constable Simon Byrne to consider the dangers posed to both his officers and the public in Northern Ireland and to suspend the use of spit hoods immediately.”