Program Protector Sinclair User has received several queries as to how a program can be protected from unauthorised users. Add this short routine by Marjan Klenovsek of Celje, Yugoslavia to your programs, and LISTing will become useless. A listing will be produced but the numbers in it will be scrambled. This gives the impression that the program listing is correct, although it will later be found on entering it that this is not the case. [A remarkable testimony to the international nature of the Spectrum community - in 1983 Yugoslavia was still behind the Iron Curtain, but they were part of us even then.]