The yobs responsible painted “UVF” on one of the walls at Trinity High School, in Renfrew.

The crooks were caught on CCTV in the grounds of the Glebe Street school at about 9.45pm on Sunday, November 23.

After entering the grounds of the building they used spray paint to emblazon the sectarian graffiti on the side of the building and then made their escape.

Worried staff spotted the graffiti - which stands for Ulster Volunteer Force, an Ulster loyalist paramilitary group in Northern Ireland who fought against the Irish Republican Army (IRA) - and contacted the police.

An investigation was launched and this week police confirmed they were treating the incident as a hate crime.

Inspector Stevie Espie, of Renfrew Community Police, said: “This is a significant crime for us and will be investigated thoroughly. We want to speak to anyone who was in the area on Sunday night, if they saw anything suspicious or anyone hanging about.

“We are keen to identify those responsible.” Anyone with information is asked to call Police Scotland’s non-emergency number, 101, or Crimestoppers, anonymously, on 0800 555 111.