No longer made, the ingenious Opera Hat (or Gibus or Chapeau Claque) consisting of silk satin stretched over a sprung steel frame, offered the perfect solution when Top Hats had to be removed and placed under theatre seats. Elegant, robust and reliable, the Opera Hat could be squashed flat and then spring up again on demand.

The Opera Hat is a fascinating, elegant machine. When it opens, it seems almost magical. When it closes, it fits inside your knapsack. If you want to go the full Fred Astaire but still travel light, it is your best choice of formal party headwear. Or, indeed, for the Opera.