Police have warned the public to call 999 immediately if they see a patient who has absconded from the John Howard Centre secure medical facility.
Shaun Deeley, 41, was in Clapton when he escaped from his minder two days ago on Saturday - January 29.
At the time he was on escorted leave from the medium secure unit in Kenworthy Road, Homerton, where he is being held as a patient.
The medical facility has been criticised in the past after a number of patients absconded.
Deeley should not be approached by members of the public, officers have warned.
The patient has links to other parts of the capital including areas in Hackney, Holloway and Finsbury Park.
CCTV footage shows Deeley wearing a grey woollen hat, a navy T-shirt, a black zip-up jacket, grey tracksuit bottoms and white trainers with blue laces when he went missing.
A spokesperson for Hackney Police said: "Can you help locate Shaun Deeley, 41, who absconded during escorted leave from a secure medical facility?
"Deeley was last seen at 3:30pm on January 29 in Clapton. He has links to Hackney, Holloway and Finsbury Park."
A spokesperson for East London NHS Foundation Trust said: "A male service user absconded from the John Howard Centre while on escorted leave.
"The Trust is working closely with the police to ensure his safe return."
The Trust has not yet confirmed whether Deeley was tagged when he escaped.
The centre provides specialist forensic psychiatric services, and some of those treated include prisoners with mental health disorders, and dangerous and severe personality disorders.
In 2015 its bosses bowed to public pressure and announced they would tag detainees on escorted leave, after the third patient went missing that year in as many months.
If you see Shaun Deeley, do not approach him but call 999, quoting reference CAD4790/29Jan.
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