Musical fun ... go judge for yourself.
The 40-strong cast from Lormac Productions began a two-week run of Trial By Jury, which pokes fun at the legal profession, to raise cash for the grade I-listed building's heritage centre.
St George's Hall has an historic link with the composers, whose works included The Pirates Of Penzance and The Mikado.
Artistic director Loraine McKinley said: "Gilbert was a solicitor who conducted legal trials in number one court room, where we are performing.
"Last year, we approached St George's Hall about performing Trial By Jury and the proceeds went to the Friends of St George's Hall.
"This year, because it was 2008, we were asked to perform it for St George's Hall heritage centre. The cast is made up of amateurs and semi-professionals from Liverpool and Wirral, aged from their 20s to 86."
Trial By Jury runs until Friday August 22. Tickets cost pounds 7. For information, call St George's Hall heritage centre on 0151-225 6909.
COURTING FAVOUR: Members of Lormac Productions presenting Trial by Jury in St George's Hall, the former crown court room where composer Gilbert once conducted trials