UK biometric residence permits are made of polycarbonate (pdf).
Bouncing the card helps to determine whether it is made of the correct material, which is stiffer and harder than many plastics. Whether the criterion is the nature of the bounce itself, or the sound it makes, or something else, I do not know.
Credit:stackoverflow.com‘
4 Mar, 2024
4 Mar, 2024
5 Mar, 2024