The raid followed public complaints from members of the public about automated calls promoting boiler and window replacement schemes.
Calls were even made to a Network Rail control centre near Fort William and as a result drivers and pedestrians were unable to check if it was safe to cross the rails at unmanned crossings.
Ken MacDonald, Head of ICO Scotland said, “these calls have caused millions of people disruption, annoyance and distress, but not only this, those made to a control centre charged with public safety may have endangered lives”.
“Companies behind nuisance calls should know that people are sick of them and when people complain to us, we will act”.
At 200 million plus calls, the firm is suspected of making the highest number of automated direct marketing calls ever investigated by the ICO and could face fines of up to £500,000.