This is a genuine London Transport Board privilege ticket, issued to Kings Cross station from the A section of the Underground network. To obtain this privilege ticket, you would have required permission from London Transport Board officials at the time, typically through a series of security checks and verification procedures.
As such, it is unlikely that anyone has obtained or can still obtain this specific ticket by simply showing up at Kings Cross station. The fact that it is marked with the A section, indicating its position in the network, suggests that it is one of the earliest tickets to be issued for a particular route.
The privilege ticket itself is relatively simple to understand, consisting of a printed permit and a unique number. It serves as proof of authorization to use the Underground system, and can be used on any London Transport Board train or bus service.