Police have made a breakthrough in the investigation into a fire that caused $27 million in damage to the Liverpool Council chambers seven years ago, revealing it may have been triggered by someone angry about a parking fine worth just a few hundred dollars.

The Hoxton Park Road building was destroyed just after midnight on August 15, 2010, with detectives believing more than one person broke into the building and set it alight using accelerant.

Historic items were lost in the fire, including mayoral robes and a picture of former Labor party leader Mark Latham as mayor. Credit:Channel Ten

Historic items were lost, including mayoral robes and a picture of former Labor party leader Mark Latham as mayor, and more than 3000 files were damaged including 600 hard copy files that had not been backed up and were completely lost.

Conspiracy theories swirled about who might have been responsible and that it may have been deliberately lit because of contentious local issues.