An teenager has admitted he brutally assaulted an elderly traffic warden outside a primary school in Perth’s south.

Colin, 87, suffered a brain bleed and broken collarbone when he was knocked to the ground during an assault near Rossmoyne Primary School on May 19.

Jatin Pudaruth, 18, then stole Colin’s hat and whistle before he fled the scene.

Bystanders helped Colin following the attack, but he drove himself home before police later visited him and took him to hospital.

He told 7News he was grateful for the community’s support and wanted to get back to work when he could.

Pudaruth pleaded guilty to assaulting a public officer and stealing in the Armadale Magistrates Court on Monday.

He will be sentenced on July 14.