Some 20 officers have sought legal advice and are working with the Scottish Police Federation (SPF) after Police Scotland failed to provide them with adequate ear protection.

Eight officers were injured after being attacked with fireworks and petrol bombs in November last year in Niddrie, in the south east of Edinburgh.

Speaking to 1919 Magazine, Gordon Forsyth, health and safety assistant to the general secretary for SPF, said: “The cops were exposed to two to three hours of constant barrage of fireworks. They’re still experiencing problems.

“Some of them may recover, but it’s likely for a few of them it will be a permanent problem, particularly the tinnitus.

“There are some who have come back to light duties – they’re probably the worst affected. For a few of them, it’s quite significant.”

Police Scotland had bought around 10,000 sets of sound suppressors, but these had not been tested by Bonfire Night and were not issued to officers.

Assistant chief constable Tim Mairs said: “These had not been public order tested in time for use during the operation, but have since been provided to officers deployed for policing the Hogmanay street party, sporting events and other major operations. A full rollout of new noise defenders is currently underway for all police officers.”