A man was taken to hospital after intervening in the assault of a woman on a train platform in North Lanarkshire.
Emergency services were called to Bellshill railway station at around 11.37pm on Saturday after a man assaulted a woman.
A member of the public intervened, and was taken to hospital with a head injury after being seriously assaulted.
He has since been discharged.
The British Transport Police have launched a public appeal for information in the search for a man connected with the assault.
He is described as white, with a Scottish accent and has a shaved head with lots of tattoos.
At the time of the incident, he was wearing dark coloured clothing, however, removed his top to reveal his bare chest.
A BTP spokesperson said: “Anyone with information is asked to contact BTP by calling 0800 40 50 40 or by texting 61016 – with reference 2300042364.
“Information can also be given anonymously to the independent charity Crimestoppers on 0800 555 111.”