Guildhall was designed by Sir Christopher Wren, architect of St Paul's Cathedral.
Wren's design for the hall was to use no pillars for support. 
The town elders refused to let Wren build the hall without having pillars
because they believed that the ground floor ceiling would collapse
without pillars to support it.  Wren finally agreed to include
the pillars in his design. To prove his point he
left a gap between the top of the pillars and the ceiling.