Opera hat described as: Some sources have taken this to describe an early folding top hat, although it is not explicitly stated whether Dollman's design was specifically for male or female headgear. Dollman's patent expired in 1825. Operating from Poissy, Paris, France, around 1840, Antoine Gibus's design for a spring-loaded collapsible top-hat proved so popular that hats made to it became known as "gibus". They were also often called "opera hats" due to the common practice of storing them in their flattened state under one's seat at the opera, though the term can also refer to any tall formal men's hat. The
Top hat Exchange that required the wearing of a top hat in the streets of the City of London was abolished by the "Big Bang" reforms of October 1986. In the British House of Commons, a rule requiring a Member of Parliament who wished to raise a point of order during a division, having to speak seated with a top hat on, was abolished in 1998. Spare top hats were kept in the chamber in case they were needed. The Modernisation Select Committee commented that "This particular practice has almost certainly brought the House into greater ridicule than almost any other". Although