THIS isn't performance art or a new sculpture installation.

In January 1987, the eyes of the world's media were on Glasgow's Barlinnie Prison, when inmates staged a dramatic rooftop protest.

A riot, sparked by claims of brutality against prisoner Sammy Ralston, saw the inmates of B Hall erupt in an orgy of violence and destruction, leading to the longest prison siege in Scottish history.

Five prison staff were taken hostage by the inmates, while others had to bar themselves in cells.

Eventually, after five days, during which a hard-core of 12 prisoners rampaged about the roof, the siege ended.

In the end, nine men stood trial for their part in the riot and three - Allan McLeish, William Marshall and Hugh Twigg - were sentenced to a total of 22 years.