by the 1980s, isc's business primarily consisted of illegal arms sales started at the behest of various us clandestine organizations. on paper the company looked to be extremely profitable on sales of high-priced "above board" items, but in fact these profits were essentially non-existent. after the sale of the company to ferranti in 1987 all illegal sales ended immediately, leaving the company with no obvious cash flow, and the merger led to the ultimate collapse of ferranti in 1991.