A man who was arrested, handcuffed and put in the back of a police van managed to set himself on fire to the station after officers missed the lighter in his pocket, a review found.
Police Scotland responded to reports of a disturbance in Arbroath and apprehended the 42-year-old at the scene.
According to an investigation by the Police Investigations and Review Commissioner (PIRC)
But the arresting officers missed the lighter he had concealed inside a knee-height pocket.
Dundee Custody Center has a special constable spotted the man taking it to the front of the house.
He suffered 'serious injuries' after being treated by the patient.
The PIRC 's investigation into the law of police in Scotland, the police, and the police.
Despite the fact that it is possible to have a complaint about the subject, it is important to consider it to be the responsibility of the officer responsible for monitoring the situation.
Police in Scotland has had the most recent experience in the field of professional conduct, effective and diligent searches to reduce the chances of a similar incident happening again.
Further advice has been issued on the risks of cuffing a person's face in front of their body when in custody.
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Superintendent Norrie Conway said: "Our officers and staff work with commitment and professionalism day in, day out, to provide a high quality policing service for the public, including those in our care.
'They work in challenging situations where they are identified, Police Scotland is committed to supporting officers and where they act in good faith.
'We have already reiterated the importance of effective searches and clarified guidance for seating arrangements in vehicles. We will reflect on the PIRC's findings to see if we can do more to improve how we serve the public.