The anniversary event, prompted by Launceston historian Gus Green, was attended by past Launceston mayors Don Wing and Clarence Pryor, as well as current aldermen and politicians.

Mayor Albert van Zetten shared his own appreciation of the town hall as a popular photographic icon for visitors and residents alike.

Alderman van Zetten referred to the words of former Tasmanian governor Thomas Gore Browne, who said the hall would one day be a ``handsome building, which would add greatly to the beauty of this city''.

``In the time since that foundation stone was laid the world has certainly changed,'' Alderman van Zetten said.

``The people who came to that ceremony on that stormy morning could not possibly have conceived that a similar gathering would come together 150 years later to celebrate their achievement.''

However, it was University of Tasmania architecture historian Anne Neal who caused a stir with her presentation about the infamous designer of the town hall.

Dr Neal said although architect Peter Mills had accepted credit for the building, it was not until its structural integrity was questioned that rogue designer Horace E. Bridges was uncovered.

She said Mr Bridges, under the false guise of Horace Bennett, was a known cheat and scam artist in Hobart and had come to Launceston on a wave of controversy before partnering with Mr Mills for the project.