Computer fraude in the '80's...

It is not something of the most recent years, not even something that started when the internet became accessible to the general public. Computer fraud happened as early as the 1980s, and then on a larger scale than you would expect. A look back to 1983 in which computers still had a fixed workplace and graphic interfaces only appeared in StarTrek.

Then, it costed the British industry already  £100 million-a-year. How did they cope back then?